Group Seminar 2019/20

Abstract:

Transport, control and conversion of spins in condensed matters have been pivotal concepts in spintronics. Spin transport is the most fundamental concept to realize spin-dependent phenomena, spin control mainly by gating enables information switching using a spin degree of freedom, and spin conversion allows detection of spins, a dissipative physical quantity. Whilst bulk metallic and semiconducting systems have been to date major material stages to realize the aforementioned concepts, low-dimensional materials systems such as atomically-flat two-dimensional materials [1-3], two-dimensional electron gases formed at an interface of a heterostructure [4,5], topologically-protected Dirac surface states in topological insulators [6,7] and ultrathin films [8] are becoming attractive materials stages to pursue novel spintronic concepts and phenomena. I will introduce the attractiveness of these new materials systems, cover an overview of the central achievements, and focus on recent investigation to pioneer novel spintronic physics in the low-dimensional materials systems.

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[2] S. Dushenko, M. Shiraishi et al., “Gate-tunable spin-charge conversion and the role of spinorbit interaction in graphene”, Phys. Rev. Lett. 116, 166102 (2016).

[3] A.W. Cummings, S. Roche et al., “Giant spin lifetime anisotropy in graphene induced by proximity effects”, Phys. Rev. Lett. 119, 206601 (2017).

[4] R. Ohshima, M. Shiraishi et al., “Strong evidence for d-electron spin transport at room temperature at a LaAlO3/SrTiO3 interface”, Nature Mater. 16, 609 (2017).

[5] E. Lesne, M. Bibes et al., “Highly efficient and tunable spin-to-charge conversion through Rashba coupling at oxide interface”, Nature Mater. 15, 1261 (2016).

[6] Y. Shiomi, E. Saitoh et al., Spin-electricity conversion induced by spin injection into topological insulators”, Phys. Rev. Lett. 113, 196601 (2014).

[7] Yuichiro Ando, M. Shiraishi et al., “Electrical detection of the spin polarization due to charge flow in the surface state of the topological insulator Bi1.5Sb0.5Te1.7Se1.3”, Nano Lett. 14, 6226 (2014).

[8] S. Dushenko, M. Shiraishi et al., “Tunable inverse spin Hall effect in nanometer-thick platinum films by ionic gating”, Nature Commun. 9, 3118 (2018).