Related papers: Microscopic origin of Heisenberg and non-Heisenber…
We calculate Heisenberg-type magnetic exchange interactions for SrMnO$_3$ under isotropic volume expansion using an approach that is based on total energy variations due to infinitesimal spin rotations around a given reference state. Our…
The exchange interaction between 5d electrons in t$_{2g}$ orbitals is derived in the J-J coupling scheme which is the appropriate basis in the case of strong spin-orbit interaction. From simple calculations, it is found that ferromagnetic…
We show for a simple non-collinear configuration of the atomistic spins (in particular, where one spin is rotated by a finite angle in a ferromagnetic background) that the pairwise energy variation computed in terms of multiple scattering…
The concept of exchange in strongly-correlated fermions is reviewed with emphasis on the generalization of the Heisenberg pair exchange to higher order n-particle permutations. The "frustration" resulting from competing ferromagnetic…
We present a detailed study of the symmetry and structure of the pairing gap in Fe-based superconductors (FeSC). We treat FeSC as quasi-2D, decompose the pairing interaction in the XY plane in s-wave and d-wave channels into contributions…
We have analyzed the magnetic interactions of a five orbital model for iron superconductors treated both within Hartree-Fock and Heisenberg approximations. We have found that the exchange constants depend non-trivially on the Fe-As-Fe angle…
Because of large spatial separation of the Mn atoms in Heusler alloys the Mn 3d states belonging to different atoms do not overlap considerably. Therefore an indirect exchange interaction between Mn atoms should play a crucial role in the…
The modern quantum theory of magnetism in solids is getting commonly derived using Green's functions formalism. The popularity draws itself from remarkable opportunities to capture the microscopic landscape of exchange interactions,…
We use first-principles calculations based on density functional theory to investigate the magnetic exchange interaction of Fe clusters on Rh(111) and Ru(0001). We consider dimers, trimers, tetramers, and pentamers of different shape in fcc…
Motivated by the on-going discussion on the nature of magnetism in the quantum Ising chain CoNb$_2$O$_6$, we present a first-principles-based analysis of its exchange interactions by applying an \textit{ab initio} approach with additional…
This work examines the magnetic order and spin dynamics of a double-exchange model with competing ferromagnetic and antiferromagnetic Heisenberg interactions between the local moments. The Heisenberg interactions are periodically arranged…
Exchange couplings are fundamental to our understanding of many physical phenomena in condensed matter physics and material science. Model systems provide a controlled environment to investigate such phenomena, effectively. In this study,…
One year after their initial discovery, two schools of thought have crystallized regarding the electronic structure and magnetic properties of ferropnictide systems. One postulates that these are itinerant weakly correlated metallic systems…
The chiral helimagnet, $Cr_{1/3}NbS_{2}$, hosts exotic spin textures, whose influence on the magneto-transport properties, make this material an ideal candidate for future spintronic applications. To date, the interplay between macroscopic…
Achieving long-range ferrimagnetic order in purely organic systems remains a major challenge in molecular magnetism. Here we report the synthesis and characterization of heterospin-coupling motifs, formed by covalently linking spin-1/2 and…
We develop a microscopic theory of multipole interactions and orderings in 5$d^2$ transition metal ion compounds. In a cubic environment, the ground state of 5$d^2$ ions is a non-Kramers $E_g$ doublet, which is nonmagnetic but hosts…
We present the results of an ab initio study of magnetic properties of Fe, Co and Ni surfaces. In particular, we discuss their electronic structure and magnetic exchange interactions (Jij), as obtained by means of a combination of density…
By means of Shubnikov-de-Haas and de-Haas-van-Alphen oscillations, and ab initio calculations, we have studied the Fermi surface of high-quality BaNiS$_2$ single crystals, with mean free path $l \sim 400 ~\text{\AA}$. The angle and…
A large class of correlated quantum materials feature strong Hund's coupling. Yet cold-atom quantum simulators have so far focused primarily on single-orbital Fermi-Hubbard systems near a Mott insulator. Here we show that repulsively…
Conventional superexchange rules predict ferromagnetic exchange interaction between Ni(II) and M (M=Mo(V), W(V), Nb(IV)). Recent experiments show that in some systems this superexchange is antiferromagnetic. To understand this feature, in…