Quantum phase transition in ultrahigh mobility SiGe/Si/SiGe two-dimensional electron system
Journal
Physical Review B
Journal Volume
99
Journal Issue
8
Date Issued
2019
Author(s)
Abstract
The metal-insulator transition (MIT) is an exceptional test bed for studying strong electron correlations in two dimensions in the presence of disorder. In the present study, it is found that in contrast to previous experiments on lower mobility samples, in ultrahigh mobility SiGe/Si/SiGe quantum wells the critical electron density nc of the MIT becomes smaller than the density nm, where the effective mass at the Fermi level tends to diverge. Near the topological phase transition expected at nm, the metallic temperature dependence of the resistance should be strengthened, which is consistent with the experimental observation of more than an order of magnitude resistance drop with decreasing temperature below ∼1 K.
Type
journal article