title: Experimental demonstration of spin geometric phase: radius dependence of time-reversal Aharonov-Casher oscillations.
abstract: A geometric phase of electron spin is studied in arrays of InAlAs/InGaAs two-dimensional electron gas rings. By increasing the radius of the rings, the time-reversal symmetric Aharonov-Casher oscillations of the electrical resistance are shifted towards weaker spin-orbit interaction regions with their shortened period. We conclude that the shift is due to a modulation of the spin geometric phase, the maximum modulation of which is approximately 1.5 rad. We further show that the Aharonov-Casher oscillations in various radius arrays collapse onto a universal curve if the radius and the strength of Rashba spin-orbit interaction are taken into account. The result is interpreted as the observation of the effective spin-dependent flux through a ring.
authors.affiliation: Graduate School of Engineering, Tohoku University, Sendai 980-8579, Japan.
authors.forename: Fumiya
authors.initials: F
authors.lastname: Nagasawa
authors.forename: Jun
authors.initials: J
authors.lastname: Takagi
authors.forename: Yoji
authors.initials: Y
authors.lastname: Kunihashi
authors.forename: Makoto
authors.initials: M
authors.lastname: Kohda
authors.forename: Junsaku
authors.initials: J
authors.lastname: Nitta