Related papers: Correlation effects in the electronic structure of…
Bulk MnBi$_2$Te$_4$ (MBT) is an intrinsic antiferromagnetic topological insulator. However, its low N\'eel temperature of $\sim 25\,\mathrm{K}$ severely restricts its practical applications. Here, we propose a van der Waals heterostructure…
Density functional calculations are used to study magnetic and electronic properties of the spinel ferrites, ZnFe$_2$O$_4$ and MnFe$_2$O$_4$. Correct magnetic orderings are obtained. ZnFe$_2$O$_4$ is predicted to be a small gap insulator in…
We present a joint experimental and theoretical characterization of the magnetic properties of coordination clusters with an antiferromagnetic core of four magnetic ions. Two different compounds are analyzed, with Co and Mn ions in the…
Mn$_3$O$_4$ is a spin frustrated magnet that adopts a tetragonally distorted spinel structure at ambient conditions and a CaMn$_2$O$_4$-type postspinel structure at high pressure. We conducted both optical measurements and \emph{ab}…
Recent magnetic measurements on tetra-nickel molecular magnets [Ni(hmp)(ROH)Cl]$_4$, where R=CH$_3$, CH$_2$CH$_3$, or (CH$_2$)$_2$C(CH$_3$)$_3$ and hmp$^-$ is the monoanion of 2-hydroxymethylpyridine, revealed a strong exchange bias prior…
We explore the interplay of electron-electron correlations and surface effects in the prototypical correlated insulating material, NiO. In particular, we compute the electronic structure, magnetic properties, and surface energies of the…
We have investigated the crystal, electronic, and magnetic structure of Mn5O8 by means of state of-the-art density functional theory calculations and neutron powder diffraction (NPD) measurements. This compound stabilizes in the monoclinic…
A new type of the single-molecule magnet [Mn_4 O_3 Cl_4 (O_2 CEt)_3(py)_3] forms dimers. Recent magnetic hysteresis measurements on this single-molecular magnet revealed interesting phenomena: an absence of quantum tunneling at zero…
Understanding the effects of electron-electron interactions in half metallic magnets (HMs), which have band structures with one gapped spin channel and one metallic channel, poses fundamental theoretical issues as well as having importance…
We describe the ground- and excited-state electronic structure of bulk MnO and NiO, two prototypical correlated electron materials, using coupled cluster theory with single and double excitations (CCSD). As a corollary, this work also…
Ab initio calculations have been carried out to study the magnetic dipole and electric quadrupole hyperfine structure constants of $^{205}$Pb$^+$. Many-body effects have been considered to all orders using the relativistic coupled-cluster…
Electronic structure and electron correlations of the Hubbard model on the Beta-Mn lattice have been investigated on the basis of the momentum dependent local ansatz wavefunction method. It is found that the electrons on the Beta-Mn lattice…
Magnetocaloric effect in [Nb$^\mathrm{IV}${($\mu$-CN)$_4$Mn$^\mathrm{II}$(H$_2$O)$_2$]}$_2\cdot$4H$_2$O]$_n$ molecular magnet is reported. The compound crystallizes in the tetragonal I4/m space group. It exhibits a phase transition to a…
Accurate density-functional based calculations have been performed on the Co_4(hmp)_4(CH_3OH)_4Cl_4 molecular magnet where hmp is deprotonated hydroxymethyl pyridine. In addition to the experimentally observed staggered geometry, we…
Magnetization, neutron diffraction and X-ray diffraction of Zn doped MnV2O4 as a function of temperature have been measured and the critical exponents and magnetocaloric effect of this system have been estimated. It is observed, that with…
A novel approach to electronic correlations in magnetic crystals which takes into account a dynamical many-body effects is present. In order to to find a frequency dependence of the electron self energy, an effective quantum-impurity…
With x-ray absorption spectroscopy we investigated the orbital reconstruction and the induced ferromagnetic moment of the interfacial Cu atoms in YBa$_2$Cu$_3$O$_{7}$/La$_{2/3}$Ca$_{1/3}$MnO$_3$ (YBCO/LCMO) and…
Strong electronic correlations are often associated with the proximity of a Mott insulating state. In recent years however, it has become increasingly clear that the Hund's rule coupling (intra-atomic exchange) is responsible for strong…
In this work we explore the performance of a recently derived many-body effective energy theory for the calculation of photoemission spectra in the regime of strong electron correlation. We apply the theory to paramagnetic MnO, FeO, CoO,…
We present a quantitative study of many-body effects including the three-particle level on second-harmonic generation in monolayer MoS$_2$. Our approach combines many-body perturbation theory with time-dependent current-density-functional…