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arXiv · 1212.1552

Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors

M. Sakano·M. S. Bahramy·A. Katayama·T. Shimojima·H. Murakawa·Y. Kaneko·W. Malaeb·S. Shin·K. Ono·H. Kumigashira·R. Arita·N. Nagaosa·H. Y. Hwang·Y. Tokura·K. Ishizaka
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Abstract

We investigate the two-dimensional (2D) highly spin-polarized electron accumulation layers commonly appearing near the surface of n-type polar semiconductors BiTeX (X = I, Br, and Cl) by angular-resolved photoemission spectroscopy. Due to the polarity and the strong spin-orbit interaction built in the bulk atomic configurations, the quantized conduction-band subbands show giant Rashba-type spin-splitting. The characteristic 2D confinement effect is clearly observed also in the valence-bands down to the binding energy of 4 eV. The X-dependent Rashba spin-orbit coupling is directly estimated from the observed spin-split subbands, which roughly scales with the inverse of the band-gap size in BiTeX.

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M. Sakano, M. S. Bahramy, A. Katayama, T. Shimojima, H. Murakawa, Y. Kaneko, W. Malaeb, S. Shin, K. Ono, H. Kumigashira, R. Arita, N. Nagaosa, H. Y. Hwang, Y. Tokura, K. Ishizaka. 2012-12-07. Strongly spin-orbit coupled two-dimensional electron gas emerging near the surface of polar semiconductors. https://doi.org/10.1103/physrevlett.110.107204

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