Phase coherent transport in (Ga,Mn)As

Abstract

Quantum interference effects and resulting quantum corrections of the conductivity have been intensively studied in disordered conductors over the last few decades. The knowledge of phase coherence lengths and underlying dephasing mechanisms are crucial in understanding quantum corrections to the resistivity in different material systems. Due to the internal magnetic field and the associated breaking of time-reversal symmetry quantum interference effects in ferromagnetic materials have scarcely been explored. Below, we describe the investigation of phase coherent transport phenomena in the newly discovered ferromagnetic semiconductor (Ga,Mn)As. We explore universal conductance fluctuations in mesoscopic (Ga,Mn)As wires and rings, the Aharonov–Bohm effect in nanoscale rings and weak localization in arrays of wires, made of the ferromagnetic semiconductor material. These experiments allow to probe the phase coherence length Lϕ and the spin flip length LSO as well as the temperature dependence of dephasing.