Three-dimensional spin rotations at the Fermi surface of a strongly spin-orbit coupled surface system.
The spin texture of the metallic two-dimensional electron system (sqrt[3]×sqrt[3])-Au/Ge(111) is revealed by fully three-dimensional spin-resolved photoemission, as well as by density functional calculations. The large hexagonal Fermi surface, generated by the Au atoms, shows a significant splitting due to spin-orbit interactions. The planar components of the spin exhibit a helical character, accompanied by a strong out-of-plane spin component with alternating signs along the six Fermi surface sections. Moreover, in-plane spin rotations toward a radial direction are observed close to the hexagon corners. Such a threefold-symmetric spin pattern is not described by the conventional Rashba model. Instead, it reveals an interplay with Dresselhaus-like spin-orbit effects as a result of the crystalline anisotropies.
Physikalisches Institut, Universität Würzburg, 97074 Würzburg, Germany.
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Höpfner
J
J
Schäfer
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A
Fleszar
J H
JH
Dil
B
B
Slomski
F
F
Meier
C
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Loho
C
C
Blumenstein
L
L
Patthey
W
W
Hanke
R
R
Claessen