报告摘要：
自巨磁电阻的发现以来，自旋电子学的研究不断发展，达到了一个新的高度自旋电流的概念，即，旋转角动量的流动，帮助我们了解各种自旋电子学的现象。这些包括所有最近发现的转换现象，如直接和反向自旋霍尔效应、自旋塞贝克效应和佩尔蒂埃效应、自旋泵浦效应和反向法拉第效应。最近,拓扑绝缘子的Rashba界面和表面状态被发现表现出所谓的Edelstein效应，其中自旋动量锁定行为导致非平衡自旋积累。因此，这些界面和表面效应提供了一个有效的手段，相互转换之间的自旋，电荷，和热电流。上述的自旋转换现象大多发生在简单的纳米级界面上在两种不同类型的材料(如磁铁、非磁铁、半导体和绝缘体)之间。这些结构可以使我们在诸如电、光、声音，振动和热量。
此次报告首先介绍一般的自旋介导的自旋转换过程，然后重点介绍导电固体中的磁电自旋转换，包括自旋霍尔效应和新的转换机制:发生在Rashba 界面[1]和拓扑绝缘子的表面状态[2]的Edelstein效应，如最近发表的文章[3]中所述。
Since the discovery of giant magnetoresistance, spintronics research has been evolving and has reached a new phase in which the concept of spin currents, i.e., the flow of spin angular momenta, helps us understand various spintronics phenomena. These include all the recently discovered conversion phenomena, such as the direct and inverse spin Hall effects, spin Seebeck and Peltier effects, spin pumping, and the inverse Faraday effect. More recently,Rashba interfaces and the surface states of topological insulators were found to exhibit the so-called Edelstein effect,in which spin-momentum locking behavior brings about non-equilibrium spin accumulation.These interface and surface effects thus provide an effective means of interconversion among spin, charge, and heat currents. Most of the above-mentioned spin conversion phenomena take place at simple nanoscale interfaces between two different types of materials (e.g., magnets, non-magnets, semiconductors, and insulators). These structures may enable us to advance spin-mediated interconversion among physical entities such as electricity, light,sound, vibration, and heat.
The repott will first give an introduction to the general spin-mediated spin-conversion processes and then will focus on magneto-electric spin conversion in conductive solids, including spin Hall effects and new conversion mechanisms:Edelstein effects arising at Rashba interfaces [1] and surface states of topological nsulators [2], as discussed in a recently published progress article [3].
[1] S. Karube, K. Kondou, and Y. Otani, “Experimental observation of spin-to-charge current conversion at non-magnetic metal/Bi2O3 interfaces,” Appl. Phys. Exp., vol. 9, 033001, 2016.
[2] K. Kondou et al., “Fermi-level-dependent charge-to-spin current conversion by Dirac surface states of topological insulators,” Nature Phys., vol. 12, pp. 1027-1031, 2016.
[3] Y. Otani et al., “Spin Conversion on the nanoscale,” Nature Phys., vol. 13, pp. 829-832, 2017.
