69 citations · 607 across the 29 of their papers we have counts for
29 papers
Electronic correlations and dynamical screening with ab initio quantum embedding
Chia-Nan Yeh, Francesco Petocchi, Alexander Hampel +4
First-principles descriptions of correlated quantum materials require a simultaneous treatment of strong local many-body effects and nonlocal dynamical screening. We present an eff…
Constrained Random Phase Approximation: the spectral method
Merzuk Kaltak, Alexander Hampel, Martin Schlipf +3
We present a constrained Random Phase Approximation (cRPA) method, termed spectral cRPA (s-cRPA), and compare it to established cRPA approaches for Scandium and Copper by varying t…
Importance of ligand on-site interactions for the description of Mott-insulators in DFT+DMFT
Alberto Carta, Anwesha Panda, Claude Ederer
Calculations combining density functional theory (DFT) and dynamical mean-field theory (DMFT) for transition metal (TM) oxides and similar compounds usually focus on improving the…
Explicit demonstration of the equivalence between DFT+U and the Hartree-Fock limit of DFT+DMFT
Alberto Carta, Iurii Timrov, Peter Mlkvik +2
Several methods have been developed to improve the predictions of density functional theory (DFT) in the case of strongly correlated electron systems. Out of these approaches, DFT+…
TRIQS/Nevanlinna: Implementation of the Nevanlinna Analytic Continuation method for noise-free data
Sergei Iskakov, Alexander Hampel, Nils Wentzell +1
We present the TRIQS/Nevanlinna analytic continuation package, an efficient implementation of the methods proposed by J. Fei et al in [Phys. Rev. Lett. 126, 056402 (2021)] and [Phy…
Dielectric environment sensitivity of carbon centres in hexagonal boron nitride
Danis I. Badrtdinov, Carlos Rodriguez-Fernandez, Magdalena Grzeszczyk +11
A key advantage of utilizing van der Waals materials as defect-hosting platforms for quantum applications is the controllable proximity of the defect to the surface or the substrat…
Conductivity of infinite-layer NdNiO as a probe of spectator bands
Harrison LaBollita, Alexander Hampel, Jonathan Karp +2
Using a density-functional theory plus dynamical mean-field theory methodology, we compute the many-body electronic structure and optical conductivity of NdNiO under the infl…
Orbital polarization, charge transfer, and fluorescence in reduced valence nickelates
M. R. Norman, A. S. Botana, J. Karp +6
This paper presents a simple formalism for calculating X-ray absorption (XAS) and resonant inelastic x-ray scattering (RIXS) that has as input orbital-resolved density of states fr…
Low rank Green's function representations applied to dynamical mean-field theory
Nan Sheng, Alexander Hampel, Sophie Beck +4
Several recent works have introduced highly compact representations of single-particle Green's functions in the imaginary time and Matsubara frequency domains, as well as efficient…
Electronic structure of the highly conductive perovskite oxide SrMoO
E. Cappelli, A. Hampel, A. Chikina +12
We use angle-resolved photoemission to map the Fermi surface and quasiparticle dispersion of bulk-like thin films of SrMoO grown by pulsed laser deposition. The electronic self…
Ab-initio investigation of Er3+ defects in tungsten disulfide
Gabriel I. López-Morales, Alexander Hampel, Gustavo E. López +3
We use density functional theory (DFT) to explore the physical properties of an point defect in monolayer . Our calculations indicate that electrons localize at…
Superconductivity and Antiferromagnetism in NdNiO and CaCuO: A Cluster DMFT Study
Jonathan Karp, Alexander Hampel, Andrew J. Millis
We perform a comparative real space cluster DMFT study on minimal models for NdNiO and CaCuO obtained from downfolding DFT states, using a Nambu formalism that…
Dynamical Mean Field Studies of Infinite Layer Nickelates: Physics Results and Methodological Implications
Hanghui Chen, Alexander Hampel, Jonathan Karp +2
This article summarizes recent work on the many-body (beyond density functional theory) electronic structure of layered rare-earth nickelates, both in the context of the materials…
The effects of strain in multi-orbital superconductors: the case of SrRuO
Sophie Beck, Alexander Hampel, Manuel Zingl +2
Uniaxial strain experiments have become a powerful tool to unveil the character of unconventional phases of electronic matter. Here we propose a combination of the superconducting…
Charge self-consistent electronic structure calculations with dynamical mean-field theory using Quantum ESPRESSO, Wannier90 and TRIQS
Sophie Beck, Alexander Hampel, Olivier Parcollet +2
We present a fully charge self-consistent implementation of dynamical mean field theory (DMFT) combined with density functional theory (DFT) for electronic structure calculations o…
Investigation of photon emitters in Ce-implanted hexagonal boron nitride
Gabriel I. López-Morales, Mingxing Li, Alexander Hampel +9
Color centers in hexagonal boron nitride (hBN) are presently attracting broad interest as a novel platform for nanoscale sensing and quantum information processing. Unfortunately,…
Sensing Strain-induced Symmetry Breaking by Reflectance Anisotropy Spectroscopy
M. Volpi, S. Beck, A. Hampel +3
Intentional breaking of the lattice symmetry in solids is a key concept to alter the properties of materials by modifying their electronic band structure. However, the correlation…
Quantum embedding methods for correlated excited states of point defects: Case studies and challenges
Lukas Muechler, Danis I. Badrtdinov, Alexander Hampel +3
A quantitative description of the excited electronic states of point defects and impurities is crucial for understanding materials properties, and possible applications of defects…
Interplay between breathing-mode distortions and magnetic order in rare-earth nickelates from magnetic models
Danis I. Badrtdinov, Alexander Hampel, Cyrus E. Dreyer
We use density-functional theory calculations to explore the magnetic properties of perovskite rare-earth nickelates, NiO, by constructing microscopic magnetic mod…
Dependence of DFT+DMFT Results on the Construction of the Correlated Orbitals
Jonathan Karp, Alexander Hampel, Andrew J. Millis
The sensitivity of Density Functional Theory plus Dynamical Mean Field Theory calculations to different constructions of the correlated orbitals is investigated via a detailed comp…
Correlation-Induced Octahedral Rotations in SrMoO
Alexander Hampel, Jeremy Lee-Hand, Antoine Georges +1
Distortions of the oxygen octahedra influence the fundamental electronic structure of perovskite oxides, such as their bandwidth and exchange interactions. Utilizing a fully ab-ini…
First-principles study of the electronic, magnetic, and crystal structure of perovskite molybdates
Jeremy Lee-Hand, Alexander Hampel, Cyrus E. Dreyer
The molybdate oxides SrMoO, PbMoO, and LaMoO are a class of metallic perovskites that exhibit interesting properties including high mobility, and unusual resistivity be…
Wavefunctions, electronic localization and bonding properties for correlated materials beyond the Kohn-Sham formalism
A. D. N. James, E. I. Harris-Lee, A. Hampel +2
Many-body theories such as dynamical mean field theory (DMFT) have enabled the description of the electron exchange-correlation interactions that are missing in current density fun…
Comparative Many-Body Study of PrNiO and NdNiO
Jonathan Karp, Alexander Hampel, Manuel Zingl +4
We study the many-body electronic structure of the stoichiometric and electron-doped trilayer nickelate PrNiO in comparison to that of the stoichiometric and hole-doped…