Benjamin Lenz
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View article: Spin-polaron fingerprints in the optical conductivity of iridates
Spin-polaron fingerprints in the optical conductivity of iridates Open
As a consequence of their spin-orbit entangled ground state, many $5d^{5}$ iridate materials display a peculiar double peak structure in optical transport quantities, such as absorption and conductivity. Their common interpretation is base…
View article: Matrix product state based band Lanczos solver for quantum cluster approaches
Matrix product state based band Lanczos solver for quantum cluster approaches Open
We present a matrix-product state (MPS) based band Lanczos method as solver for quantum cluster methods such as the variational cluster approximation. While a naïve implementation of MPS as cluster solver would barely improve its range of …
View article: On the cuprates' universal waterfall feature: evidence of a momentum-driven crossover
On the cuprates' universal waterfall feature: evidence of a momentum-driven crossover Open
We study two related universal anomalies of the spectral function of cuprates, so called waterfall and high-energy kink features, by a combined cellular dynamical mean-field theory and angle-resolved photoemission study for the oxychloride…
View article: The rich phase diagram of the prototypical iridate Ba$_2$IrO$_4$: Effective low-energy models and metal-insulator transition
The rich phase diagram of the prototypical iridate Ba$_2$IrO$_4$: Effective low-energy models and metal-insulator transition Open
In the quest of new exotic phases of matter due to the interplay of various interactions, iridates hosting a spin-orbit entangled $j_{\mathrm{eff}}=1/2$ ground state have been in the spotlight in recent years. Also in view of parallels wit…
View article: Matrix-product-state-based band-Lanczos solver for quantum cluster approaches
Matrix-product-state-based band-Lanczos solver for quantum cluster approaches Open
We present a matrix-product state (MPS) based band-Lanczos method as solver for quantum cluster methods such as the variational cluster approximation (VCA). While a naïve implementation of MPS as cluster solver would barely improve its ran…
View article: Parametrization of the Coulomb interaction matrix with point-group symmetry
Parametrization of the Coulomb interaction matrix with point-group symmetry Open
International audience
View article: Parametrization of the Coulomb interaction matrix with point-group symmetry
Parametrization of the Coulomb interaction matrix with point-group symmetry Open
Coulomb integrals, i.e., matrix elements of bare or screened Coulomb interaction between one-electron orbitals, are fundamental objects in many approaches developed to tackle the challenging problem of calculating the electronic structure …
View article: Paramagnon dispersion and damping in doped Na$_{x}$Ca$_{2-x}$CuO$_2$Cl$_2$
Paramagnon dispersion and damping in doped Na$_{x}$Ca$_{2-x}$CuO$_2$Cl$_2$ Open
Using Resonant Inelastic X-ray Scattering, we measure the paramagnon dispersion and damping of undoped, antiferromagnetic Ca$_2$CuO$_2$Cl$_2$ as well as doped, superconducting Na$_{x}$Ca$_{2-x}$CuO$_2$Cl$_2$. Our estimation of the spin-exc…
View article: Order from disorder phenomena in BaCoS$_2$
Order from disorder phenomena in BaCoS$_2$ Open
At $T_N\simeq 305~\text{K}$ the layered insulator BaCoS$_2$ transitions to a columnar antiferromagnet that signals non-negligible magnetic frustration despite the relatively high $T_N$, all the more surprising given its quasi two-dimension…
View article: Two-dimensional fluctuations and competing phases in the stripe-like antiferromagnet BaCoS$_2$
Two-dimensional fluctuations and competing phases in the stripe-like antiferromagnet BaCoS$_2$ Open
By means of a combined x-ray diffraction, magnetic susceptibility and specific heat study, we investigate the interplay between orthorhombic distortion and stripe-like antiferromagnetic (AFM) order in the Mott insulator BaCoS$_{2}$ at $T_N…
View article: Formation of CuO$_2$ sublattices by suppression of interlattice correlations in tetragonal CuO
Formation of CuO$_2$ sublattices by suppression of interlattice correlations in tetragonal CuO Open
We investigate the tetragonal phase of the binary transition metal oxide CuO (t-CuO) within the context of cellular dynamical mean-field theory. Due to its strong antiferromagnetic correlations and simple structure, analysing the physics o…
View article: Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$
Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$ Open
Obtaining an accurate theoretical description of the emergent phenomena in oxide heterostructures is a major challenge. Recently, intriguing paramagnetic spin and pinned orbital moments have been discovered by x-ray magnetic circular dichr…
View article: Report on scipost_202205_00016v1
Report on scipost_202205_00016v1 Open
We investigate the tetragonal phase of the binary transition metal oxide CuO (t-CuO) within the context of cellular dynamical mean-field theory.Due to its strong antiferromagnetic correlations and simple structure, analysing the physics of…
View article: Report on scipost_202205_00016v1
Report on scipost_202205_00016v1 Open
We investigate the tetragonal phase of the binary transition metal oxide CuO (t-CuO) within the context of cellular dynamical mean-field theory.Due to its strong antiferromagnetic correlations and simple structure, analysing the physics of…
View article: Formation of CuO$_2$ sublattices by suppression of interlattice correlations in tetragonal CuO
Formation of CuO$_2$ sublattices by suppression of interlattice correlations in tetragonal CuO Open
We investigate the tetragonal phase of the binary transition metal oxide CuO (t-CuO) within the context of cellular dynamical mean-field theory. Due to its strong antiferromagnetic correlations and simple structure, analysing the physics o…
View article: Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$
Oxygen vacancies at the origin of pinned moments in oxide interfaces: the example of tetragonal CuO/SrTiO$_3$ Open
11 pages, 9 figures
View article: Spectral functions of Sr<sub>2</sub>IrO<sub>4</sub>: theory versus experiment
Spectral functions of Sr<sub>2</sub>IrO<sub>4</sub>: theory versus experiment Open
The spin–orbit Mott insulator Sr 2 IrO 4 has attracted a lot of interest in recent years from theory and experiment due to its close connection to isostructural high-temperature copper oxide superconductors. Despite not being superconducti…
View article: Anisotropy crossover in the frustrated Hubbard model on four-chain cylinders
Anisotropy crossover in the frustrated Hubbard model on four-chain cylinders Open
Motivated by dimensional crossover in layered organic ${\\kappa}$ salts, we\ndetermine the phase diagram of a system of four periodically coupled Hubbard\nchains with frustration at half filling as a function of the interchain hopping\n${t…
View article: Variational cluster approach to superconductivity and magnetism in the Kondo lattice model
Variational cluster approach to superconductivity and magnetism in the Kondo lattice model Open
We investigate in detail antiferromagnetic (AF) and superconducting (SC)\nphases as well as their coexistence in the two-dimensional Kondo lattice model\non a square lattice, which is a paradigmatic model for heavy fermion materials.\nThe …
View article: Unconventional Phases in Two-Dimensional Hubbard and Kondo-Lattice Models by Variational Cluster Approaches
Unconventional Phases in Two-Dimensional Hubbard and Kondo-Lattice Models by Variational Cluster Approaches Open
Materials with strongly correlated electrons show a multitude of unconventional phenomena, such as superconductivity or magnetism, that cannot be explained in a single-particle picture and necessitate to take many-body effects into account…
View article: Variational cluster approach to superconductivity and magnetism in the Kondo lattice model
Variational cluster approach to superconductivity and magnetism in the Kondo lattice model Open
We investigate in detail antiferromagnetic (AF) and superconducting (SC) phases as well as their coexistence in the two-dimensional Kondo lattice model on a square lattice, which is a paradigmatic model for heavy fermion materials. The res…
View article: Mott Quantum Criticality in the Anisotropic 2D Hubbard Model
Mott Quantum Criticality in the Anisotropic 2D Hubbard Model Open
We present evidence for Mott quantum criticality in an anisotropic two-dimensional system of coupled Hubbard chains at half-filling. In this scenario emerging from variational cluster approximation and cluster dynamical mean-field theory, …