Tunable spin polarization in bismuth ultrathin film on Si(111).

Takayama, Akari; Sato, Takafumi; Souma, Seigo; Oguchi, Tamio; Takahashi, Takashi · Nano Lett · 2012

basic_science · Level V

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Abstract

We performed a spin- and angle-resolved photoemission spectroscopy of bismuth ultrathin film on Si(111) with various film thickness d. We found that the spin polarization of spin-split Rashba surface states near the Brillouin-zone boundary, which is high (0.7) at d = 40 BL (bilayers), is gradually reduced on decreasing d and almost vanishes at d = 8 BL. This finding provides a novel method to generate spin-polarized electrons with tunable spin-polarization.