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We apply the classical mapping technique developed recently by Dharma-wardana and Perrot for a study of the uniform two-dimensional electron system at arbitrary degeneracy and spin-polarization. Pair distribution functions, structure…

Strongly Correlated Electrons · Physics 2009-11-10 Nguyen Quoc Khanh , Hiroo Totsuji

Motivated by recent experiments on isovalent-doped 1111 iron-based superconductors LaFeAs$_{1-{x}}$P$_{x}$O$_{1-{y}}$F$_{y}$ and the theoretical study that followed, we investigate, within the five orbital model, the correlation between the…

Superconductivity · Physics 2015-05-20 Hayato Arai , Hidetomo Usui , Katsuhiro Suzuki , Yuki Fuseya , Kazuhiko Kuroki

Using neutron diffraction, 170Yb Mossbauer and muSR spectroscopies, we have examined the pyrochlore Yb2Ti2O7 where the Yb3+ S'=1/2 ground state has planar anisotropy. Below ~0.24K, the temperature of the known specific heat lambda…

Temperature dependent high pressure electrical resistivity studies has been carried out on Ba(Fe_{1-x}Ru_{x})_{2}As_{2} single crystals with x = 0.12, 0.26 and 0.35, which correspond to under doped, optimally doped and over doped…

Superconductivity · Physics 2014-02-17 T. R. Devidas , Awadhesh Mani , Shilpam Sharma , K. Vinod , A. Bharathi , C. S. Sundar

We study magnetic fluctuations in a system of interacting spins on a lattice at high temperatures and in the presence of a spatially varying magnetic field. Starting from a microscopic Hamiltonian we derive effective equations of motion for…

Statistical Mechanics · Physics 2013-03-28 Andrew Sykes , Dmitry Solenov , Dmitry Mozyrsky

We have studied the magnetic ordering in Na doped BaFe$_2$As$_2$ by unpolarized and polarized neutron diffraction using single crystals. Unlike previously studied FeAs-based compounds that magnetically order, Ba$_{1-x}$Na$_x$Fe$_2$As$_2$…

Superconductivity · Physics 2015-06-22 F. Wasser , A. Schneidewind , Y. Sidis , S. Aswartham , S. Wurmehl , B. Buchner , M. Braden

The effect of quantum and thermal fluctuations on the phase diagram of spin-2 BECs is examined. They are found to play an important role in the nematic part of the phase diagram, where a mean-field treatment of two-body interactions is…

Other Condensed Matter · Physics 2012-02-23 Ari Turner , Ryan Barnett , Eugene Demler , Ashvin Vishwanath

Co2FeAl0.5Si0.5 (CFAS) is a Heusler compound that is of interest for spintronics applications, due to its high spin polarization and relatively low Gilbert damping constant. In this study, the behavior of ferromagnetic resonance as a…

We present a complete description of spin injection and detection in Fe/Al_xGa_{1-x}As/GaAs heterostructures for temperatures from 2 to 295 K. Measurements of the steady-state spin polarization in the semiconductor indicate three…

Materials Science · Physics 2009-11-10 C. Adelmann , X. Lou , J. Strand , C. J. Palmstrom , P. A. Crowell

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

We present results for the dynamic structure factor of the S=1/2 bond alternating Heisenberg chain over a large range of frequencies and temperatures. Data are obtained from a numerical evaluation of thermal averages based on the…

Strongly Correlated Electrons · Physics 2009-11-11 H. -J. Mikeska , C. Luckmann

We report on the control of spin pair fluctuations using two-tone Floquet engineering. We consider a one-dimensional spin-1/2 lattice with periodically modulated spin exchanges using parametric resonances. The stroboscopic dynamics…

Quantum Physics · Physics 2024-12-25 Ruben Peña , Felipe Torres , Guillermo Romero

We develop a method for investigating nonequilibrium dynamics of an ultracold system that is initially at thermal equilibrium. Our procedure is based on the classical fields approximation with appropriately prepared initial state. As an…

Quantum Gases · Physics 2015-05-20 Emilia Witkowska , Tomasz Świsłocki , Michał Matuszewski

We investigated the characteristics of the spin fluctuations mediated superconductivity employing the Eliashberg formalism. The effective interaction between electrons was modeled in terms of the spin susceptibility measured by the…

Superconductivity · Physics 2015-06-15 Seung Hwan Hong , Han-Yong Choi

Nematic phase transitions in high-temperature superconductors have a strong impact on the electronic properties of these systems. BaFe$_2$As$_2$,\@ with an established nematic transition around 137 K induced by magnetic fluctuations, and…

Superconductivity · Physics 2021-12-01 Michael Merz , Liran Wang , Thomas Wolf , Peter Nagel , Christoph Meingast , Stefan Schuppler

We present a thorough magnetization and magneto-transport study of the diluted Fe-intercalated CrTe2 family member, Fe1/5CrTe2, a van der Waals ferromagnet. Fe1/5CrTe2 shows an elevated Curie transition temperature of 182 K in comparison to…

Strongly Correlated Electrons · Physics 2026-04-07 M. Lamba , P. Saha , K. Yadav , N. Kamboj , S. Patnaik

Understanding magnetic interactions in the parent compounds of high-temperature superconductors forms the basis for determining their role for the mechanism of superconductivity. For parent compounds of iron pnictide superconductors such as…

Skutterudites are promising materials for thermoelectric and spintronics applications. Here we explore spin fluctuations in the FeSb$_{3}$ skutterudite and their effect on its electronic structure using Hubbard-corrected density-functional…

Materials Science · Physics 2026-01-29 Enrico Di Lucente , Flaviano José dos Santos , Nicola Marzari

The spin dynamics of the layered square-lattice vanadate Pb2VO(PO4)2 is investigated by electron spin resonance at various magnetic fields and at temperatures above magnetic ordering. The linewidth divergence towards low temperatures seems…

Strongly Correlated Electrons · Physics 2013-05-29 T. Förster , F. A. Garcia , T. Gruner , E. E. Kaul , B. Schmidt , C. Geibel , J. Sichelschmidt

We study the decoherence of a spin in a quantum dot due to its hyperfine coupling to a randomly fluctuating bath of nuclear spins. The system is modelled by the central spin model with the spin bath initially being at infinite temperature.…

Mesoscale and Nanoscale Physics · Physics 2013-09-02 Alexandre Faribault , Dirk Schuricht