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We investigate multipartite entanglement in rings of arbitrary spins with antiferromagnetic interactions between nearest neighbors. In particular, we show that the non-degenerate ground state of rings formed by an even number ($N$) of spins…

Quantum Physics · Physics 2014-06-23 Ilaria Siloi , Filippo Troiani

The recent development in the field of 2D magnetic materials urges reliable theoretical methodology for determination of magnetic properties. Among the available methods, ab initio four-state energy mapping based on Density Functional…

Mesoscale and Nanoscale Physics · Physics 2020-08-05 Denis Sabani , Cihan Bacaksiz , Milorad Milosevic

We present a controlled method for computing the exchange coupling in correlated one-dimensional electron systems based on the relation between the exchange constant and the pair-correlation function of spinless electrons. This relation is…

Strongly Correlated Electrons · Physics 2007-05-23 Michael M. Fogler , Eugene Pivovarov

We study the formation of an entangled state in a one-dimensional chain of three nuclear spins system which interact weakly through the Ising type of interaction and taking into account first and second neighbor interactions. We can get…

Quantum Physics · Physics 2007-05-23 Gustavo V. Lopez , Lorena Lara

The Raman response in the antiferromagnetic 2-leg S=1/2 Heisenberg ladder is calculated for various couplings by continuous unitary transformations. For leg couplings above 80% of the rung coupling a characteristic 2-peak structure occurs…

Strongly Correlated Electrons · Physics 2009-11-07 Kai P. Schmidt , Christian Knetter , Götz S. Uhrig

We study the spatial Fourier transform of the spin correlation function G_q(t) in paramagnetic quantum crystals by direct simulation of a 1d lattice of atoms interacting via a nearest-neighbor Heisenberg exchange Hamiltonian. Since it is…

Statistical Mechanics · Physics 2009-11-11 R. Ragan , K. Grunwald , B. Batell

The antiferromagnetic Ising model on a checkerboard lattice has an ice-like ground state manifold with extensive degeneracy. and, to leading order in J_xy, deconfined spinon excitations. We explore the role of cyclic exchange arising at…

Strongly Correlated Electrons · Physics 2007-05-23 Nic Shannon , Gregoire Misguich , Karlo Penc

A new method of computing multipolar exchange interaction in spin-orbit coupled systems is developed using multipolar tensor expansion of the density matrix in LDA+U electronic structure calculation. Within mean-field approximation,…

Strongly Correlated Electrons · Physics 2014-03-06 Shu-Ting Pi , Ravindra Nanguneri , Sergey Savrasov

We consider a model of Raman scattering for a two--dimensional $S=1/2$ Heisenberg Anti-Ferromagnet which includes a {\it dynamical} spin--phonon interaction. We observe a broadening of the line shape due to increased coupling with excited…

Condensed Matter · Physics 2009-10-28 Matthew J. Reilly , A. G. Rojo

The effect of the anisotropy in the exchange interaction and film thickness on the hysteresis behavior of the anisotropic Heisenberg thin film has been investigated with effective field formulation in a two spin cluster using the decoupling…

Statistical Mechanics · Physics 2016-08-24 Ümit Akıncı , Musa Atlıhan

Using measured spin-transfer rates from alkali atoms to He-3, combined with spin-relaxation rates of the alkali atoms due to He-3 and He-4, it should be possible to differentiate between isotropic and anisotropic spin-exchange. This would…

Atomic Physics · Physics 2013-05-29 T. G. Walker , I. A. Nelson , S. Kadlecek

We present a novel approach to study the ground state and elementary excitations in compounds where spins and orbitals are entangled by on-site relativistic spin-orbit interaction. The appropriate degrees of freedom are localized states…

Strongly Correlated Electrons · Physics 2010-07-13 Gia-Wei Chern , Natalia Perkins

We present the results of band structure calculations for ACr2X4 (A=Zn, Cd, Hg and X=O, S, Se) spinels. Effective exchange coupling constants between Cr spins are determined by fitting the energy of spin spirals to a classical Heisenberg…

Other Condensed Matter · Physics 2009-11-13 A. N. Yaresko

We consider the extended Hubbard model and introduce a corresponding Heisenberg-like problem written in terms of spin operators. The derived formalism is reminiscent of Anderson's idea of the effective exchange interaction and takes into…

Strongly Correlated Electrons · Physics 2018-07-25 E. A. Stepanov , S. Brener , F. Krien , M. Harland , A. I. Lichtenstein , M. I. Katsnelson

We investigate the exchange bias and training effects in the FM/AF heterostructures using a unified Monte Carlo dynamical approach. This real dynamical method has been proved reliable and effective in simulating dynamical magnetization of…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 Kai-Cheng Zhang , Bang-Gui Liu

We investigate the phase diagram of a generalized spin-1/2 quantum antiferromagnet on a ladder with rung, leg, diagonal, and ring-exchange interactions. We consider the exactly soluble models associated with the problem, obtain the exact…

Strongly Correlated Electrons · Physics 2009-11-10 V. Gritsev , B. Normand , D. Baeriswyl

We report a study of the anisotropic exchange interactions in bulk CrO_2 calculated from first principles within density functional theory. We determine the exchange coupling energies, using both the experimental lattice parameters and…

Materials Science · Physics 2015-03-13 H. Sims , S. J. Oset , W. H. Butler , James M. MacLaren , Martijn Marsman

Motivated by recent experiments on Ba$_3$Cr$_2$O$_8$, we propose a theory describing low-temperature properties in magnetic field $h$ of dimer spin-$\frac12$ systems on a stacked triangular lattice with spatially anisotropic exchange…

Strongly Correlated Electrons · Physics 2014-05-06 O. I. Utesov , A. V. Syromyatnikov

We study systems of classical magnetic dipoles on simple cubic lattices with dipolar and antiferromagnetic exchange interactions. By analysis and Monte Carlo (MC) simulations, we find how the antiferromagnetic phases vary with uniaxial and…

Statistical Mechanics · Physics 2007-05-23 J. F. Fernandez , J. J. Alonso

The domain state model for exchange bias has been further investigated by considering vector spins for the antiferromagnet instead of Ising spins used in the earlier studies. The qualitative results are similar to those with infinite…

Statistical Mechanics · Physics 2007-05-23 A. Misra , U. Nowak , K. D. Usadel