Related papers: Spin Frustration and Orbital Order in Vanadium Spi…
Although magnetic frustration in metals provides a promising avenue for novel quantum phenomena, their microscopic interpretation is often challenging. Here we use the face-centered cubic intermetallic HoInCu$_4$ as model material to show…
We theoretically investigate the effects of charge order and spin frustration on the spin ordering in TMTTF salts. Using first-principles band calculations, we find that a diagonal inter-chain transfer integral $t_{q1}$, which causes spin…
We consider a superexchange Hamiltonian, $H=-\sum_{<i,j>}(2{\bf S}_i\cdot {\bf S}_j-\frac 12)(2{\bf T}_i\cdot {\bf T}_j-\frac 12)$, which describes systems with orbital degeneracy and strong electron-phonon coupling in the limit of large…
We investigate the highly frustrated spin and orbital superexchange interactions in cubic vanadates. The fluctuations of $t_{2g}$ orbitals trigger a {\it novel mechanism of ferromagnetic interactions} between spins S=1 of V$^{3+}$ ions…
We use exact diagonalization combined with mean-field theory to investigate the phase diagram of the spin-orbital model for cubic vanadates. The spin-orbit coupling competes with Hund's exchange and triggers a novel phase, with the ordering…
In the light of recent interesting experimental work on MgV$_2$O$_4$ we employ the density functional theory to investigate the crucial role played by different interaction parameters in deciding its electronic and magnetic properties. The…
Motivated by the recent experimental progress on the strong spin-orbit-coupled rare earth triangular antiferromagnet, we analyze the highly anisotropic spin model that describes the interaction between the spin-orbit-entangled Kramers'…
Using synchrotron X-rays and neutron diffraction we disentangle spin-lattice order in highly frustrated ZnCr$_2$O$_4$ where magnetic chromium ions occupy the vertices of regular tetrahedra. Upon cooling below 12.5 K the quandary of…
We derive a spin-orbital Hamiltonian for a triangular lattice of e_g orbital degenerate (Ni^{3+}) transition metal ions interacting via 90 degree superexchange involving (O^{2-}) anions, taking into account the on-site Coulomb interactions…
The two-dimensional frustrated next nearest neighbor Heisenberg model on the square lattice is a prime example for a spin system where quantum fluctuations can either destroy or stabilize magnetic order. The phase boundaries and staggered…
Density functional calculations are performed to study the magnetic order of the severely distorted square planar cupric oxide (CuO) and local spin disorder in it in the presence of the transition metal impurities M (= Cr, Mn, Fe, Co and…
We study the magnetic properties of metallic GaMnAs. We calculate the effective RKKY interaction between Mn spins using several realistic models for the valence band structure of GaAs. We also study the effect of positional disorder of the…
We study the effect in geometrically frustrated antiferromagnets of weak, random variations in the strength of exchange interactions. Without disorder the simplest classical models for these systems have macroscopically degenerate ground…
This paper discusses the ground state of quantum spins interacting via Heisenberg antiferromagnetic exchange, in two dimensional lattices having several different local environments. In unfrustrated lattices, when a N\'eel type order…
We study the magnetic ordering of Vanadium spinels by Quantum Monte Carlo simulations of a three-band Hubbard model. Vanadium spinels, AV$_2$O$_4$, exhibit a unique "up-up-down-down" spin ordering at low temperatures. While this magnetic…
The multiorbital Hubbard model in the strong coupling limit is analyzed for the effectively antiferromagnetic Hund's coupling relevant to fulleride superconductors with three orbitals per molecule. The localized spin-orbital model describes…
The common phase diagrams of superconducting iron pnictides show interesting material specificities in the structural and magnetic phase transitions. In some cases the two transitions are separate and second order, while in others they…
Insulating spinel materials, with the chemical formula $AB_2X_4$, behave as diamond lattice antiferromagnets when only the A-site atom is magnetic. Many exhibit classic signatures of frustration, induced not geometrically but by competing…
We explore the magnetic phases in a Kondo lattice model on the geometrically frustrated Shastry-Sutherland lattice at metallic electron densities, searching for noncollinear and noncoplanar spin textures. Motivated by experimental…
Theory of dilution effect in orbital ordered system is presented. The $e_g$ orbital model without spin degree of freedom and the spin-orbital coupled model in a three-dimensional simple-cubic lattice are analyzed by the Monte-Carlo…