Publications (62)
Models and Materials for Generalized Kitaev Magnetism
Stephen M. Winter, Alexander A. Tsirlin, Maria Daghofer +4
The exactly solvable Kitaev model on the honeycomb lattice has recently received enormous attention linked to the hope of achieving novel spin-liquid states with fractionalized Maj…
Robustness of topological edge states in alternating spin chains against environment
Alexander Sattler, Maria Daghofer
Both the Haldane spin- chain and dimerized chains of spin- exhibit topologically protected edge states that are robust against specific perturbations. Recently, such spin c…
Excitonic Magnetism at the intersection of Spin-orbit coupling and crystal-field splitting
Teresa Feldmaier, Pascal Strobel, Michael Schmid +2
Excitonic magnetism involving superpositions of singlet and triplet states is expected to arise for two holes in strongly correlated and spin-orbit coupled orbitals. Howev…
Mechanism of hole propagation in the orbital compass models
Wojciech Brzezicki, Maria Daghofer, Andrzej M. OleÅ
We explore the propagation of a single hole in the quantum compass model, whose nematic ground state is given by mutually decoupled antiferromagnetic chains. The compass model can…
Collective nature of orbital excitations in layered cuprates in the absence of apical oxygens
Leonardo Martinelli, Krzysztof Wohlfeld, Jonathan Pelliciari +19
We have investigated the 3d orbital excitations in CaCuO2 (CCO), Nd2CuO4 (NCO), and La2CuO4 (LCO) using high-resolution resonant inelastic x-ray scattering. In LCO they behave as w…
Z_2-vortex lattice in the ground state of the triangular Kitaev-Heisenberg model
Ioannis Rousochatzakis, Ulrich K. Rössler, Jeroen van den Brink +1
The triangular-lattice Heisenberg antiferromagnet (HAF) is known to carry topological Z_2 vortex excitations which form a gas at finite temperatures. Here we show that the spin-orb…
Three orbital model for the iron-based superconductors
Maria Daghofer, Andrew Nicholson, Adriana Moreo +1
The theoretical need to study the properties of the Fe-based high-T_c superconductors with reliable many-body techniques requires us to determine the minimum number of orbital degr…
Intrinsic coupling of orbital excitations to spin fluctuations in Mott insulators
Krzysztof Wohlfeld, Maria Daghofer, Satoshi Nishimoto +2
We show how the general and basic asymmetry between two fundamental degrees of freedom present in strongly correlated oxides, spin and orbital, has very profound repercussions on t…
Comment on "Nonmagnetic Impurity Resonances as a Signature of Sign-Reversal Pairing in Fe-As-Based Superconductors"
Maria Daghofer, Adriana Moreo
In a recent Letter [PRL 103, 186402 (2009)], the energy band structure of Fe-As-based superconductors is fitted with a tight-binding model with two Fe ions per unit cell and two de…
Hubbard subbands and superconductivity in the infinite-layer nickelate
Tharathep Plienbumrung, Maria Daghofer, Michael T. Schmid +1
An effective two-dimensional two-band model for infinite-layer nickelates consists of bands obtained from and --like orbitals. We investigate whether it could be m…
Comparing the influence of Floquet dynamics in various Kitaev-Heisenberg materials
Pascal Strobel, Maria Daghofer
In this paper we examine the possibility of Floquet engineering in the three candidate Kitaev materials , - and -$…
Switchable Quantum Anomalous Hall state in a strongly frustrated lattice magnet
Jörn W. F. Venderbos, Maria Daghofer, Jeroen van den Brink +1
We establish that the interplay of itinerant fermions with localized magnetic moments on a checkerboard lattice leads to magnetic flux-phases. For weak itineracy the flux-phase is…
Femtosecond dynamics of magnetic excitations from resonant inelastic x-ray scattering in CaCu2O3
Valentina Bisogni, Stefanos Kourtis, Claude Monney +10
Taking spinon excitations in the quantum antiferromagnet CaCu2O3 as an example, we demonstrate that femtosecond dynamics of magnetic excitations can be probed by direct resonant in…
Orbital-weight redistribution triggered by spin order in the pnictides
Maria Daghofer, Qinlong Luo, Rong Yu +3
The one-particle spectral function and its orbital composition are investigated in a three-orbital model for the undoped parent compounds of the iron-based superconductors. In the…
Role of Degeneracy, Hybridization, and Nesting in the Properties of Multi-Orbital Systems
Andrew Nicholson, Qinlong Luo, Weihao Ge +5
To understand the role that degeneracy, hybridization, and nesting play in the magnetic and pairing properties of multiorbital Hubbard models we here study numerically two types of…
Phenomenological Three-Orbital Spin-Fermion Model for Cuprates
Mostafa Sherif Derbala Aly Hussein, Maria Daghofer, Elbio Dagotto +1
A spin-fermion model that captures the charge-transfer properties of Cu-based high critical temperature superconductors is introduced and studied via Monte Carlo simulations. The s…
Narrowing of topological bands due to electronic orbital degrees of freedom
Jörn W. F. Venderbos, Maria Daghofer, Jeroen van den Brink
The Fractional Quantum Hall (FQH) effect has been predicted to occur in absence of magnetic fields and at high temperature in lattice systems that have flat bands with non-zero Che…
From linear to circular polarized light -- Floquet engineering in Kitaev-Heisenberg materials with Lissajous figures
Pascal Strobel, Maria Daghofer
This paper discusses Floquet engineering with arbitrary polarization in -RuCl. We describe the influence of arbitrary polarization and the limiting cases of linear and circ…
Constraints Imposed by Symmetry on Pairing Operators for the Pnictides
Xiaoyu Wang, Maria Daghofer, Andrew Nicholson +3
Considering model Hamiltonians that respect the symmetry properties of the pnictides, it is argued that pairing interactions that couple electrons at different orbitals with an orb…
Spin-Polarized Semiconductor Induced by Magnetic Impurities in Graphene
Maria Daghofer, Nan Zheng, Adriana Moreo
Magnetic impurities adsorbed on graphene are coupled magnetically via the itinerant electrons. This interaction opens a gap in the band structure of graphene. The result strongly d…
Macroscopic Degeneracy and Emergent Frustration in a Honeycomb Lattice Magnet
Jörn W. F. Venderbos, Maria Daghofer, Jeroen van den Brink +1
Using a hybrid method based on fermionic diagonalization and classical Monte Carlo, we investigate the interplay between itinerant and localized spins, with competing double- and s…
Altermagnetic polarons: the fate of alter magnetic band splittings at strong coupling
Maria Daghofer, Krzysztof Wohlfeld, Jeroen van den Brink
While a spin-dependent band splitting is one of the characteristic features of altermagnets, the conventional band picture itself breaks down in the many altermagnets that are corr…
Green's function variational approach to orbital polarons in KCuF3
Krzysztof Bieniasz, Mona Berciu, Maria Daghofer +1
We develop an orbital, --like model of a single charge doped into a two-dimensional plane with ferromagnetic spin order and alternating orbital order, and present its s…
Promising regimes for the observation of topological degeneracy in spin chains
Alexander Sattler, Maria Daghofer
Both the Haldane spin chain and a topologically dimerized chain feature topologically protected edge states that are expected to be robust against some kind of noise. To elucidate…
Competing Pairing Symmetries in a Generalized Two-Orbital Model for the Pnictides
Andrew Nicholson, Weihao Ge, Xiaotian Zhang +6
We introduce and study an extended "t-U-J" two-orbital model for the pnictides that includes Heisenberg terms deduced from the strong coupling expansion. Including these J terms ex…
On interband pairing in multiorbital systems
Adriana Moreo, Maria Daghofer, Andrew Nicholson +1
The discovery of high- superconductivity in the pnictides, materials with a Fermi surface determined by several bands, highlights the need to understand how superconductivity…
Spin-orbital physics for p orbitals in alkali RO_2 hyperoxides --- generalization of the Goodenough-Kanamori rules
Krzysztof Wohlfeld, Maria Daghofer, Andrzej M. Oles
We derive a realistic spin-orbital model at finite Hund's exchange for alkali hyperoxides. We find that, due to the geometric frustration of the oxygen lattice, spin and orbital wa…
Low Temperature Lanczos Method
Markus Aichhorn, Maria Daghofer, Hans Gerd Evertz +1
We present a modified finite temperature Lanczos method for the evaluation of dynamical and static quantities of strongly correlated electron systems that complements the finite te…
Fractional Chern insulator on a triangular lattice of strongly correlated electrons
Stefanos Kourtis, Jörn W. F. Venderbos, Maria Daghofer
We discuss the low-energy limit of three-orbital Kondo-lattice and Hubbard models describing orbitals on a triangular lattice near half-filling. We analyze how very flat b…
Dispersion of orbital excitations in 2D quantum antiferromagnets
Krzysztof Wohlfeld, Maria Daghofer, Giniyat Khaliullin +1
We map the problem of the orbital excitation (orbiton) in a 2D antiferromagnetic and ferroorbital ground state onto a problem of a hole in 2D antiferromagnet. The orbiton turns out…
Experimentally accessible scheme for a fractional Chern insulator in Rydberg atoms
Sebastian Weber, Rukmani Bai, Nastasia Makki +6
We present a setup with Rydberg atoms for the realization of a bosonic fractional Chern insulator in artificial matter. The suggested setup relies on Rydberg atoms arranged in a ho…
Nontrivial Triplon Topology and Triplon Liquid in Kitaev-Heisenberg-type Excitonic Magnets
Pavel S. Anisimov, Friedemann Aust, Giniyat Khaliullin +1
The combination of strong spin-orbit coupling and correlations, e.g. in ruthenates and iridates, has been proposed as a means to realize quantum materials with nontrivial topologic…
Spectral properties of orbital polarons in Mott insulators
Krzysztof Wohlfeld, Maria Daghofer, Andrzej M. Oles +1
We address the spectral properties of Mott insulators with orbital degrees of freedom, and investigate cases where the orbital symmetry leads to Ising-like superexchange in the orb…
Electronic correlations driving Chirality-Induced Spin Selectivity
Jacek Herbrych, Maria Daghofer
We explicitly account for electron-electron interactions when modeling low-dimensional helical organic molecules. We show that competition between various hopping channels, togethe…
Neutron and ARPES Constraints on the Couplings of the Multiorbital Hubbard Model for the Pnictides
Qinlong Luo, George Martins, Dao-Xin Yao +4
The results of neutron scattering and angle-resolved photoemission experiments for the Fe-pnictide parent compounds, and their metallic nature, are shown to impose severe constrain…
Fractional quantum-Hall liquid spontaneously generated by strongly correlated t_2g electrons
Jörn W. F. Venderbos, Stefanos Kourtis, Jeroen van den Brink +1
For topologically nontrivial and very narrow bands, Coulomb repulsion between electrons has been predicted to give rise to a spontaneous fractional quantum-Hall (FQH) state in abse…
Magnetic phases for two holes with spin-orbit coupling and crystal field
Pascal Strobel, Friedemann Aust, Maria Daghofer
We investigate two holes in the the levels of a square-lattice Mott insulator with strong spin-orbit coupling. Exact diagonalization of a spin-orbital model valid at stron…
Magnetic order in orbital models of the iron pnictides
P. M. R. Brydon, Maria Daghofer, Carsten Timm
We examine the appearance of the experimentally-observed stripe spin-density-wave magnetic order in five different orbital models of the iron pnictide parent compounds. A restricte…
Pairing Symmetries of a Hole-Doped Extended Two-Orbital Model for the Pnictides
Andrew Nicholson, Weihao Ge, José Riera +3
The hole-doped ground state of a recently introduced extended "t-U-J" two-orbital Hubbard model for the Fe-based superconductors is studied via exact diagonalization methods on sma…
From Frustrated to Unfrustrated: Coupling two triangular-lattice itinerant Quantum Magnets
Sahinur Reja, Pavel S. Anisimov, Maria Daghofer
Motivated by systems that can be seen as composed of two frustrated sublattices combined into a less frustrated total lattice, we study the double-exchange model with nearest-neigh…
Exact diagonalization results for resonant inelastic x-ray scattering spectra of one-dimensional Mott insulators
Stefanos Kourtis, Jeroen van den Brink, Maria Daghofer
We examine the momentum-dependent excitation spectra of indirect as well as direct resonant inelastic x-ray scattering (RIXS) processes in half-filled (extended) Hubbard rings. We…
Suppression of effective spin-orbit coupling by thermal fluctuations in spin-orbit coupled antiferromagnets
Jan Lotze, Maria Daghofer
We apply the finite-temperature variational cluster approach to a strongly correlated and spin-orbit coupled model for four electrons (i.e. two holes) in the subshell. We…
Interplay between Zhang-Rice singlets and high-spin states in a model for doped NiO planes
Tharathep Plienbumrung, Maria Daghofer, Andrzej M. OleÅ
Superconductivity found in doped NdNiO is puzzling as two local symmetries of doped NiO layers compete, with presumably far-reaching implications for the involved mechanism…
Mobile orbitons in CaCuO: crucial role of the Hund's exchange
Roberto Fumagalli, Jonas Heverhagen, Davide Betto +9
We investigate the Cu edge resonant inelastic x-ray scattering (RIXS) spectra of a quasi-1D antiferromagnet CaCuO. In addition to the magnetic excitations, which are…
Screening in a two-band model for superconducting infinite-layer nickelate
Tharathep Plienbumrung, Maria Daghofer, Michael Schmid +1
Starting from an effective two-dimensional two-band model for infinite layered nickelates, consisting of bands obtained from and --like orbitals, we investigate to which ext…
Jahn-Teller effect in systems with strong on-site spin-orbit coupling
Ekaterina M. Plotnikova, Maria Daghofer, Jeroen van den Brink +1
When strong spin-orbit coupling removes orbital degeneracy, it would at the same time appear to render the Jahn-Teller mechanism ineffective. We discuss such a situation, the t_2g…
Interaction-range effects for fermions in one dimension
Martin Hohenadler, Stefan Wessel, Maria Daghofer +1
Experiments on quasi-one-dimensional systems such as quantum wires and metallic chains on surfaces suggest the existence of electron-electron interactions of substantial range and…
Viewpoint: Toward Fractional Quantum Hall physics with cold atoms
Maria Daghofer, Masudul Haque
Viewpoint on Nigel R. Cooper and Jean Dalibard, "Reaching Fractional Quantum Hall States with Optical Flux Lattices", Phys. Rev. Lett. 110, 185301 (2013), and N. Y. Yao, A. V. Gors…
Electronic excitations in the Shastry-Sutherland compound SrCu(BO)
Tariq Leinen, Ola K. Forslund, Eugenio Paris +13
SrCu2(BO3)2 (SCBO) is a paradigmatic realization of the Shastry-Sutherland model, hosting geometrically frustrated spin dimers and a variety of quantum magnetic phases and phenomen…
Dynamics of a j=3/2 quantum spin liquid
Willian Natori, Maria Daghofer, Rodrigo Pereira
We study a spin-orbital model for 4 or 5 Mott insulators in ordered double perovskites with strong spin-orbit coupling. This model is conveniently written in terms of…
Phases of correlated spinless fermions on the honeycomb lattice
Maria Daghofer, Martin Hohenadler
We use exact diagonalization and cluster perturbation theory to address the role of strong interactions and quantum fluctuations for spinless fermions on the honeycomb lattice. We…
Fluctuation induced piezomagnetism in local moment altermagnets
Kostiantyn V. Yershov, Volodymyr P. Kravchuk, Maria Daghofer +1
It was recently discovered that, depending on their symmetries, collinear antiferromagnets may break spin degeneracy in momentum space, even in absence of spin-orbit coupling. Such…
Combined topological and Landau order from strong correlations in Chern bands
Stefanos Kourtis, Maria Daghofer
We present a class of states with both topological and conventional Landau order that arise out of strongly interacting spinless fermions in fractionally filled and topologically n…
Reiter's polaron wavefunction applied to a orbital t-J model
Krzysztof Wohlfeld, Andrzej M. Oles, Maria Daghofer +1
Using the self-consistent Born approximation we calculate Reiter's wavefunction for a single hole introduced into the undoped and orbitally ordered ground state of the t-J model wi…
Charge and magnetic orders in a two-band model with long-range interactions for infinite-layer nickelates NdNiO
Tharathep Plienbumrung, Jean-Baptiste Morée, Andrzej M. OleŠ+1
We present an effective two-band model for infinite-layer nickelates NdNiO that consisting of a band centered at Ni site and an interstitial -like band centered at Nd si…
Character of Doped Holes in NdSrNiO
Tharathep Plienbumrung, Michael Schmid, Maria Daghofer +1
We investigate charge distribution in the recently discovered high- superconductors, layered nickelates. With increasing value of charge-transfer energy we observe the expecte…
Spinon-orbiton repulsion and attraction mediated by Hund's rule
Jonas Heverhagen, Maria Daghofer
We study the impact of Hund's-rule coupling on orbital excitations, as e.g. measured in inelastic resonant x-ray scattering. We find that the interpretation in terms of spin-orbit…
Spectral density in a nematic state of iron pnictides
Maria Daghofer, Andrew Nicholson, Adriana Moreo
Using cluster-perturbation theory, we calculate the spectral density A(k,w) for a nematic phase of models describing pnictide superconductors, where very short-range magnetic corre…
Magnetic and Metallic State at Intermediate Hubbard U Coupling in Multiorbital Models for Undoped Fe Pnictides
Rong Yu, Kien T. Trinh, Adriana Moreo +4
Multi-orbital Hubbard model Hamiltonians for the undoped parent compounds of the Fe-pnictide superconductors are here investigated using mean-field techniques. For a realistic four…
Breaking of four-fold lattice symmetry in a model for pnictide superconductors
Maria Daghofer, André Fischer
We investigate the interplay of onsite Coulomb repulsion and various mechanisms breaking the fourfold lattice symmetry in a three-band model for the iron planes of iron-based super…
Emergent dimensional reduction of the spin sector in a model for narrow-band manganites
Shuhua Liang, Maria Daghofer, Shuai Dong +2
The widely used Double-Exchange model for manganites is shown to support various "striped" phases at filling fractions 1/n (n=3, 4, 5...), in the previously unexplored regime of na…
Robustness of the flux-free sector of the Kitaev honeycomb against environment
Alexander Sattler, Maria Daghofer
The Kitaev honeycomb model (KHM) consists of spin- particles on a honeycomb lattice with direction-dependent Ising-like interactions. It can alternatively be described in term…