Fractional conductance quantisation in low-dimensional electrons

Transport phenomena in one-dimensional (1D) quantum wires have recently gained considerable attention. Specifically, conductance quantisation at fractional values of e^2/h, without any quantizing magnetic field, has sparked considerable interest. When a weakly confined 1D channel is asymmetrically widened, several plateaus at fractional values below the first conductance plateau can be observed in high-quality electrons formed in GaAs-based heterostructures. In this work, we present recent experimental results supported by the mechanism of observation of odd and even fractional quantum plateaus in the conductance of 1D channels. Several fractional states, for example, the 2/5 and 2/3, resemble those commonly found in the Fractional Quantum Hall Effect, but without any quantising magnetic field. We will show the nature of fractional states in the presence of in-plane magnetic fields and a fixed source-drain bias [1-3].

References:

1. Kumar et al. PRL 122, 086803, (2019); APL115, 123104 (2019).

2. Kumar and Pepper, APL, 119, 110502 (2021).

3. G. Shavit and Y. Oreg, Phys. Rev. Lett. 123 036803 (2019).