462 citations · 6.7k across the 144 of their papers we have counts for
103 papers · 1 filter
Chiral magnetism and ordering of oxygen vacancies in SrTiO
Liang Si, Xiaochao Wang, Paul Worm +4
Oxygen vacancies in the perovskite insulator SrTiO free electrons that couple with other physical degrees of freedom such as lattice, orbital, and spin. This leads to the emerg…
Strain-Tuned Magnetic Frustration in a Square Lattice - Material
I. Biało, L. Martinelli, G. De Luca +16
Magnetic frustration is a route that can lead to the emergence of novel ground states, including spin liquids and spin ices. Such frustration can be introduced through either the g…
A functional-analysis derivation of the parquet equation
Christian J. Eckhardt, Patrick Kappl, Anna Kauch +1
The parquet equation is an exact field-theoretic equation known since the 60s that underlies numerous approximations to solve strongly correlated Fermion systems. Its derivation pr…
Non-linear responses and three-particle correlators in correlated electron systems exemplified by the Anderson impurity model
Patrick Kappl, Friedrich Krien, Clemens Watzenböck +1
Three-particle correlators are relevant for, among others, Raman, Hall and non-linear responses. They are also required for the next order of approximations extending dynamical mea…
Aberration of the Green's function estimator in hybridization expansion continuous-time quantum Monte Carlo
Andreas Hausoel, Markus Wallerberger, Josef Kaufmann +2
We describe an aberration of the resampling estimator for the Green's function customarily used in hybridization expansion continuous-time quantum Monte Carlo. It occurs due to Pau…
Beyond DMFT: Spin Fluctuations, Pseudogaps and Superconductivity
Karsten Held
This Chapter of the Jülich Summer School 2022 provides for a first reading on diagrammatic extensions of dynamical-mean-field theory and their application to spin fluctuations, pse…
Merging numerical renormalization group and intermediate representation to compactify two- and three-point correlators
Sebastian Huber, Markus Wallerberger, Paul Worm +1
The vanguard of many-body theory is nowadays dealing with the full frequency dynamics of n-point Green's functions for n higher than two. Numerically, these objects easily become a…
Density matrix of electrons coupled to phonons and the electron-phonon entanglement content of excited states
Gergő Roósz, Karsten Held
We derive the exact reduced density matrix for the electrons in an analytically solvable electron-phonon model. Here, the electrons are described as a Luttinger liquid that is coup…
Extended regime of coexisting metallic and insulating phases in a two-orbital electronic system
M. Vandelli, J. Kaufmann, V. Harkov +3
We investigate the metal-to-insulator phase transition driven by the density-density electronic interaction in the quarter-filled model on a cubic lattice with two orbitals split b…
Trie-based ranking of quantum many-body states
Markus Wallerberger, Karsten Held
Ranking bit patterns -- finding the index of a given pattern in an ordered sequence -- is a major bottleneck scaling up numerical quantum many-body calculations, as fermionic and h…
Zoology of spin and orbital fluctuations in ultrathin oxide films
Matthias Pickem, Josef Kaufmann, Karsten Held +1
Many metallic transition-metal oxides turn insulating when grown as films that are only a few unit-cells thick. The microscopic origins of these thickness induced metal-to-insulato…
Long-term memory magnetic correlations in the Hubbard model: A dynamical mean-field theory analysis
Clemens Watzenböck, Martina Fellinger, Karsten Held +1
We investigate the onset of a not-decaying asymptotic behavior of temporal magnetic correlations in the Hubbard model in infinite dimensions. This long-term memory feature of dynam…
Explaining the pseudogap through damping and antidamping on the Fermi surface by imaginary spin scattering
Friedrich Krien, Paul Worm, Patrick Chalupa +2
The mechanism of the pseudogap observed in hole-doped cuprates remains one of the central puzzles in condensed matter physics. We analyze this phenomenon via a Feynman-diagrammatic…
ana_cont: Python package for analytic continuation
Josef Kaufmann, Karsten Held
We present the Python package ana_cont for the analytic continuation of fermionic and bosonic many-body Green's functions by means of either the Pade approximants or the maximum en…
Comparing scattering rates from Boltzmann and dynamical mean-field theory
M. Wais, J. Kaufmann, M. Battiato +1
We compute scattering rates for electrons in the two-dimensional Hubbard model for a one-orbital metal and a two-orbital band insulator by means of the Boltzmann scattering equatio…
How correlations change the magnetic structure factor of the kagome Hubbard model
Josef Kaufmann, Klaus Steiner, Richard T. Scalettar +2
The kagome Hubbard model (KHM) is a paradigmatic example of a frustrated two-dimensional model. While its strongly correlated regime, described by a Heisenberg model, is of topical…
Broadening and sharpening of the Drude peak through antiferromagnetic fluctuations
Paul Worm, Clemens Watzenböck, Matthias Pickem +2
Antiferromagnetic or charge density wave fluctuations couple with light through the recently discovered π-ton contribution to the optical conductivity, and quite generically consti…
Self-consistent ladder DA approach
Josef Kaufmann, Christian Eckhardt, Matthias Pickem +3
We present and implement a self-consistent DA approach for multi-orbital models and ab initio materials calculations. It is applied to the one-band Hubbard model at various inte…
Tiling with triangles: parquet and methods unified
Friedrich Krien, Anna Kauch, Karsten Held
The parquet formalism and Hedin's approach are unified into a single theory of vertex corrections, corresponding to an exact reformulation of the parquet equations in terms o…
Particle-hole asymmetric lifetimes promoted by spin and orbital fluctuations in SrVO monolayers
Matthias Pickem, Jan M. Tomczak, Karsten Held
The two-dimensional nature of engineered transition-metal ultra-thin oxide films offers a large playground of yet to be fully understood physics. Here, we study pristine SrVO m…
Enhancement of impact ionization in Hubbard clusters by disorder and next-nearest-neighbor hopping
Anna Kauch, Paul Worm, Paul Prauhart +3
We perform time-resolved exact diagonalization of the Hubbard model with time dependent hoppings on small clusters of up to sites. Here, the time dependence originates from a…
Statistical error estimates in dynamical mean-field theory and extensions thereof
Patrick Kappl, Markus Wallerberger, Josef Kaufmann +2
We employ the jackknife algorithm to analyze the propagation of the statistical quantum Monte Carlo error through the Bethe--Salpeter equation. This allows us to estimate the error…
Electric-field-controllable high-spin SrRuO3 driven by a solid ionic junction
Jingdi Lu, Liang Si, Xiefei Yao +16
Controlling magnetism and spin structures in strongly correlated systems by using electric field is of fundamental importance but challenging. Here, a high-spin ruthenate phase is…
Robust skyrmion-bubble textures in SrRuO thin films stabilized by magnetic anisotropy
P. Zhang, A. Das, E. Barts +5
Topological spin textures in an itinerant ferromagnet, SrRuO is studied combining Hall transport measurements and numerical simulations. We observe characteristic signatures of…