Spin Splitting and Weak Localization in (110) GaAs/AlGaAs Quantum Wells

TL;DR

This paper explores how spin-orbit interactions influence weak localization in (110) GaAs/AlGaAs quantum wells, highlighting the effects of Dresselhaus and Rashba terms on magnetoresistance and demonstrating the unique behavior of (110) orientation.

Contribution

It provides a combined experimental and theoretical analysis of spin splitting effects on weak localization in (110) GaAs quantum wells, emphasizing the role of well orientation and spin-orbit terms.

Findings

Weak localization magnetoresistance depends on quantum well orientation.

(110) quantum wells lack an antilocalization effect without Rashba terms.

Theoretical calculations match experimental magnetoresistance data.

Abstract

We investigate experimentally and theoretically the spin-orbit effects on the weak localization in a (110) GaAs 2-dimensional electron gas (2DEG). We analyze the role of two different terms in the spin splitting of the conduction band: the Dresselhaus terms, which arise due to the lack of inversion center in the bulk GaAs, and the Rashba terms, which are caused by the asymmetry of the quantum well. It is shown that in A3B5 quantum wells the magnetoresistance due to the weak localization depends qualitatively on the orientation of the well. In particular, it is demonstrated that the (110) geometry has a distinctive feature that in the absence of the Rashba terms the ``antilocalization'' effect, i.e. the positive magnetoresistance, does not exist. Calculation of the weak anti-localization magnetoresistance is found to be in excellent agreement with experiments.