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We examine the robustness of a recently predicted exchange-induced zero-field magnetic phase in semiconductor double quantum wells in which each well is spin-polarized and the polarization vectors are antiparallel. Magnetic instabilities…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 R. J. Radtke , S. Das Sarma , A. H. MacDonald

We study intersubband spin density collective modes in double-layer quantum Hall systems at $\nu=2$ within the time-dependent Hartree-Fock approximation. We find that these intersubband spin density excitations may soften under…

Mesoscale and Nanoscale Physics · Physics 2009-10-28 Lian Zheng , R. J. Radtke , S. Das Sarma

We calculate the critical density of the zero-temperature, first-order ferromagnetic phase transition in n-doped GaAs/AlGaAs quantum wells. We find that the existence of the ferromagnetic transition is dependent upon the choice of well…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 L. O. Juri , P. I. Tamborenea

We investigate the intersubband spin-density-excitation spectrum of a double quantum well in a low-density symmetry-broken phase with interwell antiferromagnetic correlations. This spectrum is related to the intensity measured in…

Condensed Matter · Physics 2009-10-28 R. J. Radtke , S. Das Sarma

We present systematic quantitative description of the magnetoconductance of the split-gate quantum wires. Accounting for the exchange and correlation interactions within the spin density function theory (DFT) leads to the lifting of the…

Mesoscale and Nanoscale Physics · Physics 2009-05-26 I. V. Zozoulenko , S. Ihnatsenko

An argument is made on the existence of a low-temperature itinerant antiferromagnetic (AF) spin alignment, rather than persistent helical (PH), in the ground state of a two dimensional electron gas in a semiconductor quantum well with…

Mesoscale and Nanoscale Physics · Physics 2015-06-18 D. C. Marinescu

We consider various exchange-driven electronic instabilities in semiconductor double-layer systems in the absence of any external magnetic field. We establish that there is no exchange-driven bilayer to monolayer charge transfer instability…

Condensed Matter · Physics 2009-10-28 Lian Zheng , M. W. Ortalano , S. Das Sarma

We present a theory of collective spin excitations in diluted-magnetic-semiconductor quantum wells in which local magnetic moments are coupled via a quasi-two-dimensional gas of electrons or holes. In the case of a ferromagnetic state with…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Diego Frustaglia , Jürgen König , Allan H. MacDonald

We study the magnetoplasmon collective mode excitations of integer quantum Hall systems in a parabolically confined quantum well nanostructure in the presence of a tilted magnetic field by using the time-dependent Hartree-Fock…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 Daw-Wei Wang , S. Das Sarma , Eugene Demler , Bertrand I. Halperin

We present a detailed comparison of the self-consistent calculations based on the Hartree-Fock and the spin density functional theory for a spit-gate quantum wire in the IQH regime. We demonstrate that both approaches provide qualitatively…

Mesoscale and Nanoscale Physics · Physics 2009-05-26 S. Ihnatsenka , I. V. Zozoulenko

Recent claims of an experimental demonstration of spontaneous spin polarisation in dilute electron gases \cite{young99} revived long standing theoretical discussions \cite{ceper99,bloch}. In two dimensions, the stabilisation of a…

Materials Science · Physics 2009-11-11 P. Giudici , A. R. Goñi , P. G. Bolcatto , C. R. Proetto , K. Eberl , M. Hauser , C. Thomsen

We study collective spin excitations in two-dimensional diluted magnetic semiconductors, placed into external magnetic field. Two coupled modes of the spin waves (the electron and ion modes) are found to exist in the system along with a…

Mesoscale and Nanoscale Physics · Physics 2015-05-19 P. M. Shmakov , A. P. Dmitriev , V. Yu. Kachorovskii

Based on classical density functional theory (DFT), we investigate the demixing phase transition of a two-dimensional, binary Heisenberg fluid mixture. The particles in the mixture are modeled as Gaussian soft spheres, where one component…

Soft Condensed Matter · Physics 2012-08-31 K. Lichtner , A. J. Archer , S. H. L. Klapp

We study self-energy effects induced by strong magnetic fluctuations in the paramagnetic phase of strongly-correlated itinerant magnets within the density functional theory combined with the dynamical mean field theory (DFT+DMFT approach)…

Strongly Correlated Electrons · Physics 2026-04-16 A. A. Katanin

The incommensurate spin-density-wave (SDW) phase in (TMTTF)$_2$Br was investigated through transport measurements under pressure and magnetic fields parallel to the $c^{\ast}$ axis. For the incommensurate SDW phase of (TMTTF)$_2$Br…

Strongly Correlated Electrons · Physics 2009-11-10 A. Ishikawa , N. Matsunaga , K. Nomura , T. Sasaki , T. Nakamura , T. Takahashi , G. Saito

In 1962, Overhauser showed that within Hartree-Fock (HF) the electron gas is unstable to a spin density wave (SDW) instability. Determining the true HF ground state has remained a challenge. Using numerical calculations for finite systems…

Strongly Correlated Electrons · Physics 2008-06-13 Shiwei Zhang , D. M. Ceperley

The experimental studies of the paramagnetic-antiferromagnetic phase transition through M\"{o}ssbauer spectroscopy and measurements of temperature and field dependencies of magnetic susceptibility in the layered Cu$_{0.15}$Fe$_{0.85}$PS$_3$…

Computational Physics · Physics 2023-01-05 V. Pashchenko , O. Bludov , D. Baltrunas , K. Mazeika , S. Motria , K. Glukhov , Yu. Vysochanskii

We present a density-functional theory (DFT) approach to the study of the phase diagram of the maximum density droplet (MDD) in two-dimensional quantum dots in a magnetic field. Within the lowest Landau level (LLL) approximation, analytical…

Mesoscale and Nanoscale Physics · Physics 2009-10-30 M. Ferconi , G. Vignale

Fluctuations near second-order quantum phase transitions in d-wave superconductors can cause strong damping of fermionic excitations, as observed in photoemission experiments. The damping of the gapless nodal quasiparticles can arise…

Superconductivity · Physics 2025-09-08 Matthias Vojta , Subir Sachdev

The longitudinal dipole response of a quantum dot has been calculated in the far-infrared regime using local spin density functional theory. We have studied the coupling between the collective spin and density modes as a function of the…

Condensed Matter · Physics 2009-10-31 Ll. Serra , M. Barranco , A. Emperador , M. Pi , E. Lipparini
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