Role of surface anisotropy for magnetic impurities in electron dephasing and energy relaxation and their size effect

TL;DR

This paper investigates how surface anisotropy affects electron dephasing and energy relaxation caused by magnetic impurities in thin wires, revealing different influences and potential size effects that could explain experimental discrepancies.

Contribution

It provides a theoretical analysis of surface anisotropy's impact on dephasing and relaxation, highlighting their different behaviors for integer-spin impurities with singlet ground states.

Findings

Surface anisotropy influences dephasing and relaxation differently.

Size effects are significant for impurities with integer spin.

The results may explain experimental discrepancies in impurity concentration estimates.

Abstract

Recently the electron dephasing and energy relaxation due to different magnetic impurities have been extensively investigated experimentally in thin wires and in this Letter these quantities are theoretically studied. It was shown earlier that a magnetic impurity in a metallic host with strong spin-orbit interaction experiences a surface anisotropy of the form $H=K_d ({\bf n}{\bf S})^2$ which causes size effects for impurities with integer spin. Here we show that the dephasing and the energy relaxation are influenced by the surface anisotropy in very different ways for integer spin having a singlet ground state. That must result also in strong size effects and may resolve the puzzle between the concentrations estimated from the two kind of experiments.