Temperature-dependent 0.7 structure in the conductance of cleaved-edge-overgrowth one-dimensional wires

Abstract

We study the temperature dependence of the conductance in clean one-dimensional wires fabricated by cleaved-edge overgrowth in molecular beam epitaxy. At elevated temperatures, a conductance peculiarity occurs at low electron densities. The linear conductance dwells at a value of $\ensuremath{\sim}70%$ of its plateau value over a finite density range. We show that this so-called 0.7 structure arises as the electrons in the wire undergo a transition from a degenerate into a nondegenerate liquid.