Experimental study of weak antilocalization effect in a high mobility InGaAs/InP quantum well

TL;DR

This study investigates weak anti-localization effects in high mobility InGaAs/InP quantum wells, analyzing quantum interference corrections through magnetoresistance measurements across various conditions to understand phase-breaking and spin-orbit scattering.

Contribution

It provides experimental insights into quantum interference effects in high mobility quantum wells and evaluates the applicability of existing theories to fit the observed data.

Findings

Weak anti-localization effects are prominent in high mobility samples.

The characteristic magnetic field $B_{tr}$ is very small, affecting interference behavior.

A theory requiring an empirical scale factor was needed to fit the data.

Abstract

The magnetoresistance associated with quantum interference corrections in a high mobility, gated InGaAs/InP quantum well structure is studied as a function of temperature, gate voltage, and angle of the tilted magnetic field. Particular attention is paid to the experimental extraction of phase-breaking and spin-orbit scattering times when weak anti- localization effects are prominent. Compared with metals and low mobility semiconductors the characteristic magnetic field $B_{tr} = \hbar/4eD \tau$ in high mobility samples is very small and the experimental dependencies of the interference effects extend to fields several hundreds of times larger. Fitting experimental results under these conditions therefore requires theories valid for arbitrary magnetic field. It was found, however, that such a theory was unable to fit the experimental data without introducing an extra, empirical, scale factor of about 2. Measurements in tilted magnetic fields and as a function of temperature established that both the weak localization and the weak anti-localization effects have the same, orbital origin. Fits to the data confirmed that the width of the low field feature, whether a weak localization or a weak anti-localization peak, is determined by the phase-breaking time and also established that the universal (negative) magnetoresistance observed in the high field limit is associated with a temperature independent spin-orbit scattering time.