Anomalous spin-dependent behavior of one-dimensional subbands

Abstract

We report an electron interaction effect in $\mathrm{Ga}\mathrm{As}∕\mathrm{Al}\mathrm{Ga}\mathrm{As}$ quantum wires. Using dc-bias spectroscopy, we show that large and abrupt changes occur to the energies of spin-down (lower energy) states as they populate. The effect is not observed for spin-up energy states. At $B=0$, interactions have a pronounced effect, in the form of the well-known 0.7 structure. However, our results show that interactions strongly affect the energy spectrum at all magnetic fields, from $0\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}16\phantom{\rule{0.3em}{0ex}}\mathrm{T}$, not just in the vicinity of the 0.7 structure.