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

Guang-Hong Chen·M. E. Raikh
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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 $q=q_0\ll k_F$, where $q_0$ 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 $2π/q_0$. 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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Guang-Hong Chen, M. E. Raikh. 1998-09-14. Small-$q$ Anomaly in the Dielectric Function and High-Temperature Oscillations of Screening Potential in 2D Electron Gas with Spin-Orbit Coupling. https://doi.org/10.1103/physrevb.59.5090

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