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A novel, general Green's function technique for elastic spin-dependent transport calculations is presented, which (i) scales linearly with system size and (ii) allows straightforward application to general tight-binding Hamiltonians (spd in…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 S. Sanvito , C. J. Lambert , J. H. Jefferson , A. M. Bratkovsky

By employing highly sensitive millikelvin SQUID magnetometry, the magnitude of the Curie temperature as a function of the Mn concentration x is determined for thoroughly characterized Ga1-xMnxN. The interpretation of the results in the…

The $S=1/2$ Heisenberg antiferromagnet is studied on the kagom\'e lattice by using a Green's function method based on an appropriate decoupling of the equations of motion. Thermodynamic properties as well as spin-spin correlation functions…

Strongly Correlated Electrons · Physics 2009-11-07 B. H. Bernhard , B. Canals , C. Lacroix

We present a theory to study the temperature-dependent behavior of surface states in a ferromagnetic semi-infinite crystal. Our approach is based on the single-site approximation for the \emph{s-f} model. The effect of the semi-infinite…

Disordered Systems and Neural Networks · Physics 2009-11-13 Alireza Saffarzadeh

Using the Hamiltonian formulation of Composite Fermions developed recently, the temperature dependence of the spin polarization is computed for the translationally invariant fractional quantum Hall states at $\nu=1/3$ and $\nu=2/5$ in two…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Ganpathy Murthy

We develop a technique for predicting the Curie temperature of magnetic materials using density functional theory calculations suitable to include in high-throughput frameworks. We apply four different models, including physically relevant…

Atomic scale simulations at finite temperature are an ideal approach to study the thermodynamic properties of magnetic transition metals. However, the development of interatomic potentials explicitly taking into account magnetic variables…

Earlier theoretical results on $p$-$d$ and $d$-$d$ exchange interactions for zinc-blende semiconductors with $\mathrm{Cr}^{2{+}}$ and $\mathrm{Mn}^{3{+}}$ ions are revisited and extended by including contributions beyond the dominating…

Materials Science · Physics 2025-02-13 Cezary Śliwa , Tomasz Dietl

The thermodynamics of low dimensional spin-1/2 Heisenberg ferromagnets (HFM) in an external magnetic field is investigated within a second-order two-time Green function formalism in the wide temperature and field range. A crucial point of…

Strongly Correlated Electrons · Physics 2009-11-13 T. N. Antsygina , M. I. Poltavskaya , I. I. Poltavsky , K. A. Chishko

We discribe a simple way to derive spin correlation functions in 2D Ising model at critical temperature but with nonzero magnetic field at the boundary. Local magnetization (i.e. one-point function) is computed explicitly for half-plane and…

High Energy Physics - Theory · Physics 2015-06-26 R. Chatterjee , A. Zamolodchikov

Temperature-dependent magnetic properties of Nd$_2$Fe$_{14}$B permanent magnets, i.e., saturation magnetization $M_\text{s}(T)$, effective magnetic anisotropy constants $K_i^\text{eff}(T)$ ($i=1,2,3$), domain wall width $\delta_w(T)$, and…

Materials Science · Physics 2019-06-18 Qihua Gong , Min Yi , Richard F. L. Evans , Bai-Xiang Xu , Oliver Gutfleisch

The magnetic behavior of bcc iron nanoclusters, with diameters between 2 and 8 nm, is investigated by means of spin dynamics (SD) simulations coupled to molecular dynamics (MD-SD), using a distance-dependent exchange interaction.…

Mesoscale and Nanoscale Physics · Physics 2020-11-25 G. Dos Santos , R. Aparicio , D. Linares , E. N. Miranda , J. Tranchida , G. M. Pastor , E. M. Bringa

We consider a Hubbard model with occupation dependent hopping integrals. Using the Hartree-Fock (H-F) approximation and the new Green function approach with inter-site kinetic averages included, we analyze the influence of the correlated…

Strongly Correlated Electrons · Physics 2013-12-12 Grzegorz Górski , Jerzy Mizia , Krzysztof Kucab

Magnetic anisotropy is crucial for sustaining long range magnetic order in two-dimensional materials (2D) and must be taken into account by any approximate scheme for calculating critical temperatures. While 2D ferromagnets have received…

Materials Science · Physics 2026-02-18 Varun Rajeev Pavizhakumari , Thomas Olsen

We present a theoretical scheme to calculate the elastic constants of magnetic materials in the high-temperature paramagnetic state. Our approach is based on a combination of disordered local moments picture and ab initio molecular dynamics…

Materials Science · Physics 2016-08-24 Elham Mozafari , Nina Shulumba , Peter Steneteg , Björn Alling , Igor A. Abrikosov

We present an ab initio investigation of magnetic exchange interactions using the spin-spiral method implemented in the VASP code, with a comparative analysis of the self-consistent (SC) and magnetic force theorem (MFT) approaches. Using…

Materials Science · Physics 2025-10-30 Umit Dogan Daglum , Maria Stamenova , Ersoy Sasioglu , Stefano Sanvito

While the ground state of magnetic materials is in general well described on the basis of spin density functional theory (SDFT), the theoretical description of finite-temperature and non-equilibrium properties require an extension beyond…

Materials Science · Physics 2022-06-22 Sergiy Mankovsky , Hubert Ebert

The finite-temperature magnetic properties of Fe$_x$Pd$_{1-x}$ and Co$_x$Pt$_{1-x}$ alloys have been investigated. It is shown that the temperature-dependent magnetic behaviour of alloys, composed of originally magnetic and non-magnetic…

Materials Science · Physics 2015-05-19 S. Polesya , S. Mankovsky , O. Sipr , and W. Meindl , C. Strunk , H. Ebert

The equations-of-motion (EOM) hierarchy satisfied by the Green functions of a quantum dot embedded in an external mesoscopic network is considered within a high-order decoupling approximation scheme. Exact analytic solutions of the…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Vyacheslavs Kashcheyevs , Amnon Aharony , Ora Entin-Wohlman

Investigation of magnetic materials at realistic conditions with first-principles methods is a challenging task due to the interplay of vibrational and magnetic degrees of freedom. The most difficult contribution to include in simulations…

Materials Science · Physics 2020-07-08 Davide Gambino , Marian Arale Brännvall , Amanda Ehn , Ylva Hedström , Björn Alling