Self-Organised Fractional Quantisation in a Hole Quantum Wire

TL;DR

This paper explores fractional quantisation phenomena in hole quantum wires, revealing new quantised conductance levels indicative of charge fractionalisation, with potential implications for quantum transport understanding.

Contribution

It reports the observation of fractional quantised conductance levels in hole quantum wires, a novel phenomenon not previously documented in such systems.

Findings

Observation of quantised conductance at n=1/4, 1/8, and 1/32

Detection of charge fractionalisation effects in quantum wires

Plateaux unaffected by magnetic field at certain levels

Abstract

We have investigated hole transport in one-dimensional quantum wires in strained germanium two-dimensional layers. The ballistic conductance characteristics show the regular quantised plateaux in units of n2e2/h, where n is an integer. Additionally, new quantised levels are formed which correspond to values of n = 1/4 reducing to 1/8 in the presence of a strong parallel magnetic field which lifts the spin degeneracy but does not quantise the wavefunction. A further plateau is observed corresponding to n = 1/32 which does not change in the presence of a parallel magnetic field. These values indicate that the system is behaving as if charge was fractionalised with values e/2 and e/4, possible mechanisms are discussed.