Journal of Physics, Condensed Matter 2012-10-10

Probing temperature-driven flow lines in a gated two-dimensional electron gas with tunable spin-splitting.

Yi-Ting Wang, Gil-Ho Kim, C F Huang, Shun-Tsung Lo, Wei-Jen Chen, J T Nicholls, Li-Hung Lin, D A Ritchie, Y H Chang, C-T Liang, B P Dolan

Index: J. Phys. Condens. Matter 24(40) , 405801, (2012)

Full Text: HTML

Abstract

We study the temperature flow of conductivities in a gated GaAs two-dimensional electron gas (2DEG) containing self-assembled InAs dots and compare the results with recent theoretical predictions. By changing the gate voltage, we are able to tune the 2DEG density and thus vary disorder and spin-splitting. Data for both the spin-resolved and spin-degenerate phase transitions are presented, the former collapsing to the latter with decreasing gate voltage and/or decreasing spin-splitting. The experimental results support a recent theory, based on modular symmetry, which predicts how the critical Hall conductivity varies with spin-splitting.