Magnetic-Field-Induced V-Shaped Quantized Conductance Staircase in a Double-Layer Quantum Point Contact;Physical Review B (Rapid Communication)

摘要

We show that the low-temperature conductance (G) of a quantum point contact consisting of ballistic tunnel-coupled double-layer quantum well wires is modulated by an in-layer magnetic field B(sub (parallel)) perpendicular to the wires due to the anticrossing. In a system with a small g factor, B(sub (parallel)) creates a V-shaped quantum staircase for G, causing it to decrease in steps of 2e(sup 2)/(Dirac-h) to a minimum and then increase to a maximum value, where G may saturate or decrease again at higher B(sub (parallel))'s. The effect of B(sub (parallel))-induced mass enhancement and spin splitting is studied. The relevance of the results to recent data is discussed.