講演情報
[17p-M_101-8]Mesoscopic Interference of Rotated Spins in Graphene on High-Spin-Orbit-Coupling Substrates
〇Jonathan Paul Bird3, Kazushi Yokoi1, Ratchanok Somphonsane2, Harihara Ramamoorthy2, Nargess Arabchigavkani3, Jonas Fransson4, Kenji Watanabe5, Takashi Taniguchi5, Nobuyuki Aoki1 (1.Chiba Univ., 2.King Mongkut Univ., 3.Univ. at Buffalo, 4.Uppsala Univ., 5.NIMS)
キーワード：
2D semiconductors、Spin-orbit coupling、Weak antilocalization
We explore the manifestations of spin rotation in graphene in proximity with two different types of high-spin-orbit-coupling (SOC) material (ferromagnetic Co and nominally diamagnetic WSe2). Using weak antilocalization (WAL) as a probe of the induced rotation, we demonstrate that spin interference exhibits a highly stochastic (non-self-averaging) character in the mesoscopic limit. At low temperatures (<20 K), the spin rotation is manifested as a zero-bias peak (or zero-bias anomaly, ZBA) in the differential conductance, a feature that, as expected for WAL, is suppressed by fairly modest magnetic fields (<~102 mT). The ZBA moreover exhibits a stochastic variation when a gate voltage is used to sweep the Fermi level through the graphene bands, with ranges for which the antilocalization is either prominent or strongly suppressed. This mesoscopic character is exhibited by both of the studied systems, whose ZBA is also damped in similar fashion with increasing temperature. We thus provide fundamental insight into the non-ensemble-averaged (non-self-averaged) character of spin interference in mesoscopic systems with strong SOC – more specifically, into how the details of spin rotation are impacted by external gating. This understanding may ultimately enable the efficient modulation of spin currents in future spintronic devices.