Small-q Anomaly in the Dielectric Function and High-Temperature Oscillations of Screening Potential in 2D Electron Gas with Spin-Orbit Coupling

1998/09/14 by Guang-Hong Chen, M. E. Raikh · 1 citation
Physics and Astronomy · #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevb.59.5090

15 pages, REVTeX, 5 figures

arxiv created 1998/09/14 · arxiv updated 2009/11/30

Abstract

We study the static dielectric function ε(q) of 2D electron system with spin-orbit coupling in the frame of the random phase approximation. We demonstrate that, in addition to the well-known 2k_F-Kohn anomaly, spin-orbit coupling gives rise to the novel anomaly in the dielectric function at small q=q₀≪ k_F, where q₀ is the distance between two Fermi surfaces. As a result of this anomaly a large-distance behavior of the potential from a point charge exhibits (in addition to the conventional Friedel oscillations) novel oscillations with a period 2π/q₀. The remarkable feature of these oscillations is that they are not smeared out by the temperature. We show that the small-q anomaly also modifies the indirect exchange interaction of localized magnetic moments (RKKY interaction). In the presense of spin-orbit coupling this interaction acquires a high-temperature component.

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