Spin-orbit interaction and the 'metal-insulator' transition observed in two-dimensional hole systems

Abstract

We present calculations of the spin and phase relaxation rates in GaAs/AlGaAs $p$-type quantum wells. These rates are used to derive the temperature dependence of the weak-localization correction to the conductivity. In $p$-type quantum wells both weak localization and weak anti-localization are present due to the strong spin-orbit interaction. When determining the total conductivity correction one also have to include the term due to hole-hole interaction. The magnitude of the latter depends on the ratio between the thermal energy and the Fermi energy, $k_{\mathrm{B}}T/E_{\mathrm{F}}$ and whether the system can be considered as ballistic $(k_{\mathrm{B}}T{\tau }_{\mathrm{tr}}/\hslash >1)$ or diffusive ($k_{\mathrm{B}}T{\tau }_{\mathrm{tr}}/\hslash <1$). We argue that due to the relatively low Fermi energy and the moderate mobilities, in the $p$-type systems in question, the conductivity correction arising from hole-hole interactions is negligible at the highest temperatures accessible in the experiments. Hence the 'metal-insulator' transition observed at these relatively high temperatures could be caused by interference effects. We compare our calculations of the weak anti-localization correction with the experimental results from different independent groups with special emphasis on the experiments by Simmons et al. We find good agreement between predicted and observed transistion density $p_c$.

6 pages, 4 figures. Accepted to PRB (15 June, 2002)

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• Weak localisation in AlGaAs/GaAs p-type quantum wells
• Quantum conductivity corrections in two dimensional long-range disordered systems with strong spin-orbit splitting of electron spectrum

Cited by in corpus (5)

• Magnetoresistance and dephasing in a two-dimensional electron gas at intermediate conductances
• Antilocalization and spin-orbit coupling in hole strained GaAs/InGaAs/GaAs quantum well heterostructures
• Interference-induced magnetoresistance in HgTe quantum wells
• Interference induced metallic-like behavior of a two-dimensional hole gas in asymmetric GaAs/In${}_x$Ga${}_{1-x}$As/GaAs quantum well
• Weak localization of holes in high-mobility heterostructures