Quantum ballistic transport in in-plane-gate transistors showing onset of a novel ferromagnetic phase transition

TL;DR

This paper investigates one-dimensional electron transport in in-plane-gate transistors, revealing conductance plateaux at e^2/h indicative of a novel ferromagnetic phase transition driven by many-electron effects.

Contribution

It reports the experimental observation of conductance quantization at e^2/h in in-plane-gate transistors, suggesting a new ballistic ferromagnetic ground state not explained by existing theories.

Findings

Observation of conductance plateaux at e^2/h and multiples of 2e^2/h

Evidence of a ferromagnetic phase transition in 1D electron systems

Identification of a many-electron effect causing novel ground state

Abstract

We study one-dimensional transport in focused-ion-beam written in-plane-gate transistors on III-V heterostructures at moderately low temperatures at zero bias without any external magnetic field applied. In accordance with a recent proposal of A. Gold and L. Calmels, Valley- and spin-occupancy instability in the quasi-one-dimensional electron gas, Phil. Mag. Lett. 74, 33-42 (1996) and earlier experimental data, we observe plateaux in the source-drain conductivity considered as a function of the gate voltage, not only at multliples of 2e^2/h but also clearly at e^2/h, just before the channel closes to zero conductivity. This may be interpreted as a many electron effect, namely as a novel ballistic ferromagnetic ground state evading standard descriptions and theorems.