Publications (132)
Anomalous amplitude mode dynamics below the expected charge-density-wave transition in 1-VSe
Charles J. Sayers, Giovanni Marini, Matteo Calandra +6
A charge-density-wave (CDW) is characterized by a dynamical order parameter consisting of a time-dependent amplitude and phase, which manifest as optically-active collective modes…
Why Mercury is a superconductor
Cesare Tresca, Gianni Profeta, Giovanni Marini +4
Despite being the oldest known superconductor, solid mercury is mysteriously absent from all current computational databases of superconductors. In this work, we present a critical…
Anharmonic phonons in few layer MoS: Raman spectroscopy of ultra low energy compression and shear modes
Mohamed Boukhicha, Matteo Calandra, Marie-Aude Measson +2
Molybdenum disulfide (MoS) is a promising material for making two-dimensional crystals and flexible electronic and optoelectronic devices at the nanoscale. MoS flakes can s…
Infrared resonance Raman of bilayer graphene: signatures of massive fermions and band structure on the 2D peak
Lorenzo Graziotto, Francesco Macheda, Tommaso Venanzi +14
Few-layer graphene possesses low-energy carriers which behave as massive fermions, exhibiting intriguing properties in both transport and light scattering experiments. Lowering the…
Antiferromagnetic stripe phase and large-gap insulating ground state of the correlated ~R30-Sn/Si(111) single atomic layer
Mohammadmehdi Torkzadeh, Mattia Iannetti, Mathieu Lizée +10
The one-third monolayer Sn layer on Si(111) has long been considered a benchmark system for exploring two-dimensional Mott physics, owing to its narrow bandwidth and sizable on-sit…
Protection of Ising spin-orbit coupling in bulk misfit superconductors
Tomas Samuely, Darshana Wickramaratne, Martin Gmitra +16
Low-dimensional materials have remarkable properties that are distinct from their bulk counterparts. A paradigmatic example is Ising superconductivity that occurs in monolayer mate…
Two-dimensional Fröhlich interaction in transition-metal dichalcogenide monolayers: Theoretical modeling and first-principles calculations
Thibault Sohier, Matteo Calandra, Francesco Mauri
We perform ab initio calculations of the coupling between electrons and small-momentum polar-optical phonons in monolayer transition metal dichalcogenides of the 2H type: MoS2, MoS…
Ultrafast creation of a light induced semimetallic state in strongly excited 1T-TiSe
Maximilian Huber, Yi Lin, Giovanni Marini +5
Screening, a ubiquitous phenomenon associated with the shielding of electric fields by surrounding charges, has been widely adopted as a means to modify a material's properties. Wh…
Gate Tunable Magnetism and Giant Magnetoresistance in ABC-stacked Few-Layer Graphene
Yongjin Lee, Shi Che, Jairo Velasco +6
Magnetism is a prototypical phenomenon of quantum collective state, and has found ubiquitous applications in semiconductor technologies such as dynamic random access memory (DRAM).…
Density functional perturbation theory for gated two-dimensional heterostructures: Theoretical developments and application to flexural phonons in graphene
Thibault Sohier, Matteo Calandra, Francesco Mauri
The ability to perform first-principles calculations of electronic and vibrational properties of two-dimensional heterostructures in a field-effect setup is crucial for the underst…
Thermal conductivity of BiSe from bulk to thin films: theory and experiment
Lorenzo Paulatto, Danièle Fournier, Massimiliano Marangolo +3
We calculate the lattice-driven in-plane and out-of-plane thermal conductivities of BiSe bulk, and of films of different thicknesses, usin…
Phonon-assisted magnetic Mott-insulating state in the charge density wave phase of single-layer 1TNbSe2
Matteo Calandra
We study the structural, electronic and vibrational properties of single-layer 1TNbSe from first principles. Within the generalized gradient approximation, the 1T polytype is h…
Anharmonicity and the isotope effect in superconducting lithium at high pressures: a first-principles approach
Miguel Borinaga, Unai Aseginolaza, Ion Errea +3
Recent experiments [Schaeffer 2015] have shown that lithium presents an extremely anomalous isotope effect in the 15-25 GPa pressure range. In this article we have calculated the a…
Electronic and vibrational properties of in the charge-density wave phase from first principles
Raffaello Bianco, Matteo Calandra, Francesco Mauri
We study the charge-density wave phase in by using first principle calculations. We show that, regardless of the local functional used and as long as the cell par…
Hydrogen sulphide at high pressure: a strongly-anharmonic phonon-mediated superconductor
Ion Errea, Matteo Calandra, Chris J . Pickard +7
We use first principles calculations to study structural, vibrational and superconducting properties of HS at pressures GPa. The inclusion of zero point energy leads…
Possibility of superconductivity in graphite intercalated with alkaline earths investigated with density functional theory
Matteo Calandra, Francesco Mauri
Using density functional theory we investigate the occurrence of superconductivity in AC with A=Mg,Ca,Sr,Ba. We predict that at zero pressure, Ba and Sr should be superconducti…
Electronic structure and magnetic properties of few-layer CrGeTe: the key role of nonlocal electron-electron interaction effects
Guido Menichetti, Matteo Calandra, Marco Polini
Atomically-thin magnetic crystals have been recently isolated experimentally, greatly expanding the family of two-dimensional materials. In this Article we present an extensive com…
Quantum effects in muon spin spectroscopy within the stochastic self-consistent harmonic approximation
Ifeanyi John Onuorah, Pietro BonfÃ, Roberto De Renzi +4
In muon spin rotation experiments the positive implanted muon vibrates with large zero point amplitude by virtue of its light mass. Quantum mechanical calculations of the host mate…
Fermi surface geometry and momentum dependent electron-phonon coupling drive the charge density wave in quasi-1D ZrTe
Josu Diego, Matteo Calandra
ZrTe is a prototypical quasi-one-dimensional compound undergoing a charge density wave transition via a very sharp Kohn anomaly in phonon momentum space. While Fermi surface ge…
Light-Induced Transient Polarization Reversal in Rhombohedrally Stacked Bilayer Transition-Metal Dichalcogenides via an Electronic Mechanism
Xiangzhou Zhu, Stefano Mocatti, Matteo Calandra
Light-induced sliding ferroelectricity in two-dimensional van der Waals materials enables polarization control via relative layer motion. However, polarization switching occurs on…
High- superconductivity in weakly electron-doped HfNCl
Betül Pamuk, Francesco Mauri, Matteo Calandra
We investigate the magnetic and superconducting properties in electron-doped LiHfNCl. HfNCl is a band insulator that undergoes an insulator to superconductor transition upon do…
Electron-phonon coupling and phonon self-energy in MgB: do we really understand MgB Raman spectra ?
Matteo Calandra, Francesco Mauri
We consider a model Hamiltonian fitted on the ab-initio band structure to describe the electron-phonon coupling between the electronic bands and the phonon E mode in Mg…
Charge density wave and spin insulating state in single layer 1T-NbS
Cesare Tresca, Matteo Calandra
In bulk samples and few layer flakes, the transition metal dichalcogenides NbS and NbSe assume the H polytype structure with trigonal prismatic coordination of the Nb atom.…
Quantum Crystal Structure in the 250 K Superconducting Lanthanum Hydride
Ion Errea, Francesco Belli, Lorenzo Monacelli +8
The discovery of superconductivity at 200 K in the hydrogen sulfide system at large pressures [1] was a clear demonstration that hydrogen-rich materials can be high-temperature sup…
Determination of scattering time and of valley occupation in transition-metal dichalcogenides doped by field effect
Thomas Brumme, Matteo Calandra, Francesco Mauri
The transition-metal dichalcogenides have attracted a lot of attention as a possible stepping-stone toward atomically thin and flexible field-effect transistors. One key parameter…
Anharmonic phonon frequency shift in MgB2
Michele Lazzeri, Matteo Calandra, Francesco Mauri
We compute the anharmonic shift of the phonon frequencies in MgB2, using density functional theory. We explicitly take into account the scattering between different phonon modes at…
Electronic structure of TiSe from a quasi-self-consistent GW approach
Maria Hellgren, Lucas Baguet, Matteo Calandra +2
In a previous work it was shown that the inclusion of exact exchange is essential for a first principles description of both the electronic- and the vibrational properties of TiSe$…
Giant non-adiabatic effects in layer metals: Raman spectra of intercalated graphite explained
A. Marco Saitta, Michele Lazzeri, Matteo Calandra +1
The occurrence of non-adiabatic effects in the vibrational properties of metals have been predicted since the 60's, but hardly confirmed experimentally. We report the first fully \…
Born effective charges and vibrational spectra in super and bad conducting metals
Guglielmo Marchese, Francesco Macheda, Luca Binci +3
Interactions mediated by electron-phonon coupling are responsible for important cooperative phenomena in metals such as superconductivity and charge-density waves. The same interac…
Breakdown of optical phonons' splitting in two-dimensional materials
Thibault Sohier, Marco Gibertini, Matteo Calandra +2
We investigate the long-wavelength dispersion of longitudinal and transverse optical phonon modes in polar two-dimensional materials, multilayers, and their heterostructures. Using…
First-Principles Theory of Anharmonicity and the Inverse Isotope Effect in Superconducting Palladium-Hydride Compounds
Ion Errea, Matteo Calandra, Francesco Mauri
Palladium hydrides display the largest isotope effect anomaly known in literature. Replacement of hydrogen with the heavier isotopes leads to higher superconducting temperatures, a…
Ultrafast magnetization induced by linearly polarized pulses is widespread in nonmagnetic semiconductors
Xiangzhou Zhu, Junfeng Qiao, Nicola Marzari +1
Ultrafast optical on-off switching of magnetic order promises near-petahertz information processing. Recently, it has been proposed that non-magnetic semiconductors with narrow ban…
Spin susceptibility and electron-phonon coupling of two-dimensional materials by range-separated hybrid density functionals: Case study of LiZrNCl
Betül Pamuk, Jacopo Baima, Roberto Dovesi +2
We investigate the capability of density functional theory (DFT) to appropriately describe the spin susceptibility, , and the intervalley electron-phonon coupling in LiZr…
Local and non-local electron-phonon couplings in K3Picene and the effect of metallic screening
Michele Casula, Matteo Calandra, Francesco Mauri
We analyze the properties of electron-phonon couplings in K3Picene by exploiting a molecular orbital representation derived in the maximally localized Wannier function formalism. T…
Misfit layer compounds: a platform for heavily-doped two-dimensional transition metal dichalcogenides
Raphaël T. Leriche, Alexandra Palacio-Morales, Marco Campetella +14
Transition metal dichalcogenides (TMDs) display a rich variety of instabilities such as spin and charge orders, Ising superconductivity and topological properties. Their physical p…
Universal enhancement of superconductivity in two dimensional semiconductors at low doping by electron-electron interaction
Matteo Calandra, Paolo Zoccante, Francesco Mauri
In two-dimensional multivalley semiconductors, at low doping, even a moderate electron-electron interaction enhances the response to any perturbation inducing a valley polarization…
Exchange Enhancement of the Electron-Phonon Interaction: the Case of Weakly Doped Two-Dimensional Multivalley Semiconductors
Betul Pamuk, Paolo Zoccante, Jacopo Baima +2
The effect of the exchange interaction on the vibrational properties and on the electron-phonon coupling were investigated in several recent works. In most of the case, exchange te…
Superconductivity in C6Ca
Matteo Calandra, Francesco Mauri
Using density functional theory we demonstrate that superconductivity in C6Ca is due to a phonon-mediated mechanism with electron-phonon coupling 0.83 and phonon-frequency logarith…
The Raman fingerprint of rhombohedral graphite
Abderrezak Torche, Francesco Mauri, Jean-Christophe Charlier +1
Multi-layer graphene with rhombohedral stacking is a promising carbon phase possibly displaying correlated states like magnetism or superconductivity due to the occurrence of a fla…
Electrochemical doping of few layer ZrNCl from first-principles: electronic and structural properties in field-effect configuration
Thomas Brumme, Matteo Calandra, Francesco Mauri
We develop a first-principles theoretical approach to doping in field-effect devices. The method allows for calculation of the electronic structure as well as complete structural r…
Weak Dimensionality Dependence and Dominant Role of Ionic Fluctuations in the Charge-Density-Wave Transition of NbSe
Raffaello Bianco, Lorenzo Monacelli, Matteo Calandra +2
Contradictory experiments have been reported about the dimensionality effect on the charge-density-wave transition in 2H NbSe. While scanning tunnelling experiments on single l…
Phonon collapse and van der Waals melting of the 3D charge density wave of VSe
Josu Diego, A. H. Said, S. K. Mahatha +7
Among transition metal dichalcogenides (TMDs), VSe is considered to develop a purely 3-dimensional (3D) charge-density wave (CDW) at T=110 K. Here, by means of high res…
Electronic band structure of Two-Dimensional WS2/Graphene van der Waals Heterostructures
Hugo Henck, Zeineb Ben Aziza, Debora Pierucci +13
Combining single-layer two-dimensional semiconducting transition metal dichalcogenides (TMDs) with graphene layer in van der Waals heterostructures offers an intriguing means of co…
Light-Induced Nonthermal Phase Transition to the Topological Crystalline Insulator State in SnSe
Stefano Mocatti, Giovanni Marini, Matteo Calandra
Femtosecond pulses have been used to reveal hidden broken symmetry states and induce transitions to metastable states. However, these states are mostly transient and disappear afte…
Competition between exchange-driven dimerization and magnetism in diamond(111)
Betül Pamuk, Matteo Calandra
Strong electron-electron interaction in ultraflat edge states can be responsible for correlated phases of matter, such as magnetism, charge density wave or superconductivity. Here…
Adiabatic and non-adiabatic phonon dispersion in a Wannier function approach
Matteo Calandra, Gianni Profeta, Francesco Mauri
We develop a first-principles scheme to calculate adiabatic and non-adiabatic phonon frequencies in the full Brillouin zone. The method relies on the variational properties of a fo…
NbSe's charge density wave collapse in the (LaSe)(NbSe) misfit layer compound
Ludovica Zullo, Grégory Setnikar, Amit Pawbake +8
Misfit layer compounds, heterostructures composed by a regular alternating stacking of rocksalt monochalcogenides bilayers and few-layer transition metal dichalchogenides, are an e…
Black metal hydrogen above 360 GPa driven by proton quantum fluctuations
Lorenzo Monacelli, Ion Errea, Matteo Calandra +1
Production of metallic hydrogen is one of the top three open quests of physics. Recent low-temperature experiments report different metallization pressures, varying from 360GPa to…
First-principles calculations of phonon frequencies, lifetimes and spectral functions from weak to strong anharmonicity: the example of palladium hydrides
Lorenzo Paulatto, Ion Errea, Matteo Calandra +1
The variational stochastic self-consistent harmonic approximation is combined with the calculation of third-order anharmonic coefficients within density-functional perturbation the…
Phonon dispersion and lifetimes in MgB2
Abhay Shukla, Matteo Calandra, Matteo d'Astuto +9
We measure phonon dispersion and linewidth in a single crystal of MgB_2 along the Gamma-A, Gamma-M and A-L directions using inelastic X-Ray scattering. We use Density Functional Th…
Anharmonic phonon spectra of PbTe and SnTe in the self-consistent harmonic approximation
Guilherme A. Ribeiro, Lorenzo Paulatto, Raffaello Bianco +3
At room temperature, PbTe and SnTe are efficient thermoelectrics with a cubic structure. At low temperature, SnTe undergoes a ferroelectric transition with a critical temperature s…
The Stochastic Self-Consistent Harmonic Approximation: Calculating Vibrational Properties of Materials with Full Quantum and Anharmonic Effects
Lorenzo Monacelli, Raffaello Bianco, Marco Cherubini +3
The efficient and accurate calculation of how ionic quantum and thermal fluctuations impact the free energy of a crystal, its atomic structure, and phonon spectrum is one of the ma…
Flat Electronic Bands in Long Sequences of Rhombohedral-stacked Multilayer Graphene
Hugo Henck, Jose Avila, Zeineb Ben Aziza +15
The crystallographic stacking order in multilayer graphene plays an important role in determining its electronic properties. It has been predicted that a rhombohedral (ABC) stackin…
Thermodynamic stabilities of ternary metal borides: An ab initio guide for synthesizing layered superconductors
Aleksey N. Kolmogorov, Matteo Calandra, Stefano Curtarolo
Density functional theory calculations have been used to identify stable layered Li--B crystal structure phases derived from a recently proposed binary metal-sandwich (MS) lithi…
Critical role of the exchange interaction for the electronic structure and charge-density-wave formation in TiSe2
Maria Hellgren, Jacopo Baima, Raffaello Bianco +3
We show that the inclusion of screened exchange via hybrid functionals provides a unified description of the electronic and vibrational properties of TiSe2. In contrast to local ap…
Pressure and stress tensor of complex anharmonic crystals within the stochastic self-consistent harmonic approximation
Lorenzo Monacelli, Ion Errea, Matteo Calandra +1
The self-consisted harmonic approximation (SCHA) allows the computation of free energy of anharmonic crystals considering both quantum and thermal fluctuations. Recently, a stochas…
Strong anharmonicity and high thermoelectric efficiency in high temperature SnS from first-principles
Unai Aseginolaza, Raffaello Bianco, Lorenzo Monacelli +5
SnS and SnSe are isoelectronic materials with a common phase diagram. Recently, SnSe was found to be the most efficient intrinsic thermoelectric material in its high-temperature Cm…
Discovery of magnetic-field-tunable density waves in a layered altermagnet
Christopher Candelora, Muxian Xu, Siyu Cheng +11
Altermagnets recently came into the spotlight as a new class of magnetic materials, arising as a consequence of specific crystal symmetries. They are characterized by a spin-polari…
Second order structural phase transitions, free energy curvature, and temperature-dependent anharmonic phonons in the self-consistent harmonic approximation: theory and stochastic implementation
Raffaello Bianco, Ion Errea, Lorenzo Paulatto +2
The self-consistent harmonic approximation is an effective harmonic theory to calculate the free energy of systems with strongly anharmonic atomic vibrations, and its stochastic im…
Theory of infrared magneto-optical effects from chiral phonons in solids
Chiara Fiorazzo, Cheol-Hwan Park, Ivo Souza +1
In crystals with broken time-reversal symmetry, zone-center phonons can acquire a finite angular momentum via velocity-dependent forces on the nuclei. Despite having the same order…
Nonequilibrium Photocarrier and Phonon Dynamics from First Principles: a Unified Treatment of Carrier-Carrier, Carrier-Phonon, and Phonon-Phonon Scattering
Stefano Mocatti, Giovanni Marini, Giulio Volpato +2
We develop a first-principles many-body framework to describe the dynamics of photocarriers and phonons in semiconductors following ultrafast excitation. Our approach incorporates…
Quantum Hydrogen-Bond Symmetrization and High-Temperature Superconductivity in Hydrogen Sulfide
Ion Errea, Matteo Calandra, Chris J. Pickard +7
Hydrogen compounds are peculiar as the quantum nature of the proton can crucially affect their structural and physical properties. A remarkable example are the high-pressure phases…
Superconductivity from doping boron icosahedra
Matteo Calandra, Nathalie Vast, Francesco Mauri
We propose a new route to achieve the superconducting state in Boron-rich solids, the hole doping of B icosahedra. For this purpose we consider a prototype metallic phase of…
Misfit layer compounds as ultra-tunable field effect transistors: from charge transfer control to emergent superconductivity
Ludovica Zullo, Giovanni Marini, Tristan Cren +1
Misfit layer compounds are heterostructures composed of rocksalt units stacked with few layers transition metal dichalcogenides. They host Ising superconductivity, charge density w…
Ab-initio energetics of graphite and multilayer graphene: stability of Bernal versus rhombohedral stacking
Jean Paul Nery, Matteo Calandra, Francesco Mauri
There has been a lot of excitement around the observation of superconductivity in twisted bilayer graphene, associated to flat bands close to the Fermi level. Such correlated elect…
Highly tunable optics across a topological transition in organic polymers
Davide Romanin, Matteo Calandra, Alex W. Chin
Controllable topological phase transitions are appealing as they allow for tunable single particle electronic properties. Here, by using state-of-the-art manybody perturbation theo…
Probing enhanced electron-phonon coupling in graphene by infrared resonance Raman spectroscopy
Tommaso Venanzi, Lorenzo Graziotto, Francesco Macheda +16
We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV on graphene, to study how low-energy carriers interact with lattice vibrations.…
Electric field exfoliation and high-T superconductivity in field-effect hole-doped hydrogenated diamond (111)
Davide Romanin, Thibault Sohier, Dario Daghero +3
We investigate the possible occurrence of field-effect induced superconductivity in the hydrogenated diamond surface by first-principles calculations. By computing the band…
Theory of ultrafast magnetization of non-magnetic semiconductors with localized conduction bands
Giovanni Marini, Matteo Calandra
The magnetization of a non-magnetic semiconductor by femtosecond light pulses is crucial to achieve an all-optical control of the spin dynamics in materials and to develop faster m…
Anharmonic suppression of Charge density wave in 2H-NbS
Maxime Leroux, Mathieu Le Tacon, Matteo Calandra +6
The temperature dependence of the phonon spectrum in the superconducting transition metal dichalcogenide 2H-NbS is measured by diffuse and inelastic x-ray scattering. A deep, w…
Theory of the thickness dependence of the charge density wave transition in 1T-TiTe
Jianqiang Sky Zhou, Raffaello Bianco, Lorenzo Monacelli +3
Most metallic transition metal dichalcogenides undergo charge density wave (CDW) instabilities with similar or identical ordering vectors in bulk and in single layer, albeit with d…
First-principles theory of field-effect doping in transition-metal dichalcogenides: Structural properties, electronic structure, Hall coefficient, and electrical conductivity
Thomas Brumme, Matteo Calandra, Francesco Mauri
We investigate how field-effect doping affects the structural properties, the electronic structure and the Hall coefficient of few-layers transition metal dichalcogenides by using…
High T superconductivity in superhard diamond-like BC
Matteo Calandra, Francesco Mauri
Using density functional theory calculations we show that the recently-synthesized, superhard diamond-like BC is superconducting with a critical temperature of the same order t…
High pressure tuning of magnon-polarons in the layered antiferromagnet FePS
Amit Pawbake, Thomas Pelini, Alex Delhomme +9
Magnetic layered materials have emerged recently as promising systems to introduce magnetism in structures based on two-dimensional (2D) materials and to investigate exotic magneti…
High-pressure phase diagram of hydrogen and deuterium sulfides from first principles: structural and vibrational properties including quantum and anharmonic effects
Raffaello Bianco, Ion Errea, Matteo Calandra +1
We study the structural and vibrational properties of the high-temperature superconducting sulfur trihydride and trideuteride in the high-pressure and phases by…
Temperature-dependent anharmonic phonons in quantum paraelectric KTaO by first principles and machine-learned force fields
Luigi Ranalli, Carla Verdi, Lorenzo Monacelli +3
Understanding collective phenomena in quantum materials from first principles is a promising route toward engineering materials properties on demand and designing new functionaliti…
Intrinsic vibrational angular momentum from non-adiabatic effects in non-collinear magnetic molecules
Oliviero Bistoni, Francesco Mauri, Matteo Calandra
We show that in non-collinear magnetic molecules, non-adiabatic (dynamical) effects due to the electron-vibron coupling are time-reversal symmetry breaking interactions for the vib…
Strong anharmonicity induces quantum melting of charge density wave in 2H-NbSe under pressure
Maxime Leroux, Ion Errea, Mathieu Le Tacon +7
The interplay between charge density wave (CDW) order and superconductivity has attracted much attention. This is the central issue of along standing debate in simple transition me…
Chemically-exfoliated single-layer MoS : stability, lattice dynamics and catalytic adsorption from first principles
Matteo Calandra
Chemically and mechanically exfoliated MoS single-layer samples have substantially different properties. While mechanically exfoliated single-layers are mono-phase (1H polytype…
Disorder-Driven Enhancement of Coulomb Repulsion Governs The Superconducting Dome in Ionic-Liquid-Gated Quasi-2D Materials
Giovanni Marini, Pierluigi Cudazzo, Matteo Calandra
The superconducting dome in the Tc versus doping phase diagram, found in cuprates, nickelates, twisted bilayer graphene, and transition metal dichalcogenides, is often considered a…
Electron-Phonon Interactions and the Intrinsic Electrical Resistivity of Graphene
Cheol-Hwan Park, Nicola Bonini, Thibault Sohier +5
We present a first-principles study of the temperature- and density-dependent intrinsic electrical resistivity of graphene. We use density-functional theory and density-functional…
Photoinduced phase heterogeneity and charge localization in SnSe
Benjamin J. Dringoli, Stefano Mocatti, Giovanni Marini +4
Time-resolved multi-terahertz (THz) spectroscopy is used to observe pump fluence-dependent dynamics in the optical conductivity of photoexcited tin selenide (SnSe) over an ultrabro…
Phonon Collapse and Second-Order Phase Transition in Thermoelectric SnSe
Unai Aseginolaza, Raffaello Bianco, Lorenzo Monacelli +5
Since 2014 the layered semiconductor SnSe in the high-temperature Cmcm phase is known to be the most efficient thermoelectric material. Making use of first-principles calculations…
Charge density wave in single-layer Pb/Ge(111) driven by Pb-substrate exchange interaction
Cesare Tresca, Matteo Calandra
Single layer Pb on top of (111) surfaces of group IV semiconductors hosts charge density wave and superconductivity depending on the coverage and on the substrate. These systems ar…
Intercalant and intermolecular phonon assisted superconductivity in K-doped picene
Michele Casula, Matteo Calandra, Gianni Profeta +1
K-picene is a superconducting molecular crystal with critical temperature TK or 18K, depending on preparation conditions. Using density functional theory we show that ele…
First principles calculations of X-ray absorption in an ultrasoft pseudopotentials scheme: from -quartz to high-T compounds
Christos Gougoussis, Matteo Calandra, Ari P. Seitsonen +1
We develop a first-principles scheme based on the continued fraction approach an d ultrasoft pseudopotentials to calculate K-edge X-ray absorption spectra in solids. The method all…
Exponential localization of Wannier functions in insulators
Christian Brouder, Gianluca Panati, Matteo Calandra +2
The exponential localization of Wannier functions in two or three dimensions is proven for all insulators that display time-reversal symmetry, settling a long-standing conjecture.…
Anharmonic melting of the charge density wave in single-layer TiSe2
Jianqiang Sky Zhou, Lorenzo Monacelli, Raffaello Bianco +3
Low dimensional systems with a vanishing band-gap and a large electron-hole interaction have been proposed to be unstable towards exciton formation. As the exciton binding energy i…
Symmetry-protected electronic metastability in an optically driven cuprate ladder
Hari Padma, Filippo Glerean, Sophia F. R. TenHuisen +23
Optically excited quantum materials exhibit nonequilibrium states with remarkable emergent properties, but these phenomena are usually transient, decaying on picosecond timescales…
How to make graphene superconducting
Gianni Profeta, Matteo Calandra, Francesco Mauri
Graphene is the physical realization of many fundamental concepts and phenomena in solid state-physics, but in the long list of graphene remarkable properties, a fundamental block…
Charge density wave and superconducting dome in TiSe2 from electron-phonon interaction
Matteo Calandra, Francesco Mauri
At low temperature TiSe2 undergoes a charge density wave instability. Superconductivity is stabilized either by pressure or by Cu intercalation. We show that the pressure phase dia…
Density-functional calculation of static screening in 2D materials: the long-wavelength dielectric function of graphene
Thibault Sohier, Matteo Calandra, Francesco Mauri
We calculate the long-wavelength static screening properties of both neutral and doped graphene in the framework of density-functional theory. We use a plane-wave approach with per…
Multi-scale theoretical approach to X-ray absorption spectra in disordered systems: an application to the study of Zn(II) in water
Francesco Stellato, Matteo Calandra, Francesco D'Acapito +4
We develop a multi-scale theoretical approach aimed at calculating from first principles X-ray absorption spectra of liquid solutions and disordered systems. We test the method by…
Hybrid-functional electronic structure of multilayer graphene
Marco Campetella, Nguyen Minh Nguyen, Jacopo Baima +3
Multilayer graphene with rhombohedral and Bernal stacking are supposed to be metallic, as predicted by density functional theory calculations using semi-local functionals. However…
Long-range rhombohedral-stacked graphene through shear
Jean Paul Nery, Matteo Calandra, Francesco Mauri
The discovery of superconductivity and correlated electronic states in the flat bands of twisted bilayer graphene has raised a lot of excitement. Flat bands also occur in multilaye…
Light-tunable charge density wave orders in MoTe2 and WTe2 single layers
Giovanni Marini, Matteo Calandra
By using constrained density functional theory modeling, we demonstrate that ultrafast optical pumping unveils hidden charge orders in group VI monolayer transition metal ditelluri…
Optical absorption and photoluminescence of single layer boron nitride from a first principles cumulant approach
Giovanni Marini, Matteo Calandra, Pierluigi Cudazzo
The photoluminescence spectrum of a single-layer boron nitride remains elusive, marked by enigmatic satellites that hint at a significant but unidentified exciton-phonon coupling.H…
Electron-phonon driven charge density wave in CuTe
Marco Campetella, Giovanni Marini, Jianqiang Sky Zhou +1
The compound CuTe (vulcanite) undergoes a quasi one dimensional charge density wave (CDW) at K with a periodicity. The mechanism at its…
Density functional theory description of hole-trapping in SiO: a successful self-interaction-corrected approach
Mayeul d'Avezac, Matteo Calandra, Francesco Mauri
We present a self-interaction-corrected (SIC) density-functional-theory (DFT) approach for the description of systems with an unpaired electron or hole such as spin 1/2 defect-cent…
Doping tunable charge density waves in misfit layer compounds
Hugo Le Du, Ludovica Zullo, Justine Cordiez +14
The ability to tune charge density waves (CDWs) through external control knobs, such as doping, pressure or strain is crucial for exploring the phase diagram of two dimensional (2D…