“You need another gate, mate”: g-factor engineering in quantum wires and wrap-gated nanowires

1D systems have received significant attention as possible spin-filtering elements [3,4] and for studying fundamental spin/exchange-based phenomena [5]. An important parameter in both cases is the Landé effective g-factor g*, which relates the Zeeman spin-splitting to the applied magnetic field. The g-factor sets the minimum applied field required to resolve the spin, providing incentive to maximise its value, and gives some insight into exchange effects. Despite this, little is known about how the g* of a QPC's 1D subbands evolves with electron density, and precisely how this plays into many-body effects such as the anomalous 0.7 × 2e
²
/h plateau, which remains an open scientific problem.