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Large Bychkov-Rashba spin-orbit coupling in high-mobility GaN/AlGaN heterostructures

S. Schmult·M. J. Manfra·A. Punnoose·A. M. Sergent·K. W. Baldwin·R. J. Molnar
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Abstract

We present low temperature magnetoconductivity measurements of a density-tunable and high mobility two-dimensional electron gas confined in the wide bandgap GaN/AlGaN system. We observed pronounced anti-localization minima in the low-field conductivity, indicating the presence of strong spin-orbit coupling. Density dependent measurements of magnetoconductivity indicate that the coupling is mainly due to the Bychkov-Rashba mechanism. In addition, we have derived a closed-form expression for the magnetoconductivity, allowing us to extract reliable transport parameters for our devices. The Rashba spin-orbit coupling constant is $α_{so}$ $\sim$ 6$\times$ 10$^{-13}$eVm, while the conduction band spin-orbit splitting energy amounts to $Δ_{so}$ $\sim$ 0.3meV at n$_e$=1$\times10^{16}$m$^{-2}$.

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S. Schmult, M. J. Manfra, A. Punnoose, A. M. Sergent, K. W. Baldwin, R. J. Molnar. 2006-05-08. Large Bychkov-Rashba spin-orbit coupling in high-mobility GaN/AlGaN heterostructures. https://doi.org/10.1103/physrevb.74.033302

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