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A systematic investigation of the microscopic conditions stabilizing itinerant ferromagnetism of correlated electrons in a single-band model is presented. Quantitative results are obtained by quantum Monte Carlo simulations for a model with…

Strongly Correlated Electrons · Physics 2009-10-30 J. Wahle , N. Blümer , J. Schlipf , K. Held , D. Vollhardt

This contribution summarises the theoretical basics for the theory of x-ray matter interaction and is based on a quantised description of the electromagnetic field. In view of a formally transparent presentation, we adopt the approach of…

Quantum Physics · Physics 2018-11-30 Nina Rohringer

Ultracold neutral plasmas provide a useful system for studying extreme parameter regimes plasma physics in an accessible laboratory setting. The parameter space of plasma physics can be characterized in part by coupling strength and degree…

Plasma Physics · Physics 2026-02-27 Ryan C. Baker , Bridget O'Mara , Jacob L. Roberts

An unusual increase of the conductance with temperature is observed in clean quantum point contacts for conductances larger than 2e^2/h. At the same time a positive magnetoresistance arises at high temperatures. A model accounting for…

Mesoscale and Nanoscale Physics · Physics 2011-01-25 Vincent Thomas Francois Renard , O. A. Tkachenko , V. A. Tkachenko , T. Ota , N. Kumada , J. -C. Portal , Y. Hirayama

Spin-lattice dynamics is used to study the magnetic properties of Fe foams. The temperature dependence of the magnetization in foams is determined as a function of the fraction of surface atoms in foams, nsurf. The Curie temperature of…

We use combine high resolution neutron diffraction (HRPD) with density functional theory (DFT) to investigate the exchange striction at the Curie temperature (TC) of Fe2P and to examine the effect of boron and carbon doping on the P site.…

Materials Science · Physics 2013-07-26 Z. Gercsi , E. K. Delczeg-Czirjak , L. Vitos , A. S. Wills , A. Daoud-Aladine , K. G. Sandeman

We study the magnetic orbital response of a system of N interacting electrons confined in a two-dimensional geometry and subjected to a perpendicular magnetic field in the finite temperature Hartree-Fock approximation. The electron-electron…

Mesoscale and Nanoscale Physics · Physics 2009-01-23 L. G. G. V. Dias da Silva , Caio H. Lewenkopf , Nelson Studart

The magnetic response of strongly localized electrons to a time-dependent vector potential is considered. The orbital magnetic moment of the system, away from steady-state conditions, is obtained. The expression involves the tunneling and…

Condensed Matter · Physics 2009-10-28 Y. Galperin , O. Entin-Wohlman

When an ordered spin system of a given dimensionality undergoes a second order phase transition the dependence of the order parameter i.e. magnetization on temperature can be well-described by thermal excitations of elementary collective…

Materials Science · Physics 2017-03-30 H. J. Qin , Kh. Zakeri , A. Ernst , J. Kirschner

The one--loop effective action for a slowly varying electromagnetic field is computed at finite temperature and density using a real-time formalism. We discuss the gauge invariance of the result. Corrections to the Debye mass from an…

High Energy Physics - Theory · Physics 2009-10-28 Per Elmfors , Bo-Sture Skagerstam

We numerically study a Bose-Hubbard ring of finite size with disorder containing a finite number of bosons that are subject to an on-site two-body interaction. Our results show that moderate interactions induce dynamical thermalization in…

Quantum Gases · Physics 2016-01-27 Peter Schlagheck , Dima L. Shepelyansky

The influence of uncorrelated (nonmagnetic) overlayers on the magnetic properties of thin itinerant-electron films is investigated within the single-band Hubbard model. The Coulomb correlation between the electrons in the ferromagnetic…

Strongly Correlated Electrons · Physics 2009-10-31 J. H. Wu , T. Herrmann , W. Nolting

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…

Materials Science · Physics 2015-05-13 M. D. Johannes , Igor Mazin

The density of states and chemical potential as functions of temperature and filling degree of energy band were calculated. It was shown the peculiarity of concentration and temperature behavior of chemical potential is stipulated by Fermi…

Materials Science · Physics 2012-05-29 B. V. Karpenko , A. V. Kuznetsov , A. A. Bogolubova

Atomistic spin model simulations are immensely useful in determining temperature dependent magnetic prop- erties, but are known to give the incorrect dependence of the magnetization on temperature compared to exper- iment owing to their…

Mesoscale and Nanoscale Physics · Physics 2015-05-12 R. F. L. Evans , U. Atxitia , R. W. Chantrell

We present a new dynamical approach for measuring the temperature of a Hamiltonian dynamical system in the micro canonical ensemble of thermodynamics. We show that under the hypothesis of ergodicity the temperature can be computed as a…

chao-dyn · Physics 2009-10-30 Hans Henrik Rugh

We propose a method for modeling the magnetic properties of nanomaterials with different structures. The method is based on the Ising model and the approximation of the random field interaction. It is shown that in this approximation, the…

General Physics · Physics 2015-06-11 Yury Kirienko , Leonid Afremov

We consider a small metallic particle (quantum dot) where ferromagnetism arises as a consequence of Stoner instability. When the particle is connected to electrodes, exchange of electrons between the particle and the electrodes leads to a…

Mesoscale and Nanoscale Physics · Physics 2009-03-30 D. M. Basko , M. G. Vavilov

We study the interaction-induced quantum correction \delta\sigma_{\alpha\beta} to the conductivity tensor of electrons in two dimensions for arbitrary T\tau (where T is the temperature and \tau the transport scattering time), magnetic…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 I. V. Gornyi , A. D. Mirlin

We show that the critical temperature of a ferromagnetic phase transition in a quasi-two-dimensional hole gas confined in a diluted magnetic semiconductor quantum well strongly depends on the hole chemical potential and hole density. The…

Mesoscale and Nanoscale Physics · Physics 2017-11-22 P. S. Grigoryev , M. M. Glazov , A. V. Kavokin , A. A. Varlamov