Weak-localization corrections to the conductivity of double quantum wells

TL;DR

This paper analyzes how weak-localization effects influence the conductivity of double quantum wells under magnetic fields, revealing dependencies on tunneling, magnetic field orientation, and interlayer parameters.

Contribution

It provides a detailed evaluation of weak-localization corrections in double quantum wells, including effects of magnetic fields and tunneling, extending understanding beyond single-layer systems.

Findings

Conductivity correction depends on magnetic field orientation and tunneling time.

Parallel magnetic fields can increase conductivity in certain regimes.

Diffusion coefficient modifications occur in coherent tunneling regimes.

Abstract

The weak-localization contribution \delta\sigma(B) to the conductivity of a tunnel-coupled double-layer electron system is evaluated and its behavior in weak magnetic fields B perpendicular or parallel to the layers is examined. In a perpendicular field B, \delta \sigma(B) increases and remains dependent on tunneling as long as the magnetic field is smaller than \hbar/e D \tau_t, where D is the in-plane diffusion coefficient and \tau_t the interlayer tunneling time. If \tau_t is smaller than the inelastic scattering time, a parallel magnetic field also leads to a considerable increase of the concuctivity starting with a B**2 law and saturating at fields higher than \hbar/e Z (D \tau_t)**(1/2), where Z is the interlayer distance. In the limit of coherent tunneling, when \tau_t is comparable to elastic scattering time, \delta \sigma(B) differs from that of a single-layer system due to ensuing modifications of the diffusion coefficient. A possibility to probe the weak-localization effect in double-layer systems by the dependence of the conductivity on the gate-controlled level splitting is discussed.