Institut des Nanosciences et l'Energie Atomique et Cryogénie, INAC, Commissariat á aux Energies Alternatives-Univ. Grenoble Alpes, 17 rue des Martyrs, F-38000 Grenoble, France.
CEA, INAC, F-38000 Grenoble, France.
Nat Commun. 2016 Dec 15;7:13857. doi: 10.1038/ncomms13857.
The spin-orbit coupling relating the electron spin and momentum allows for spin generation, detection and manipulation. It thus fulfils the three basic functions of the spin field-effect transistor. However, the spin Hall effect in bulk germanium is too weak to produce spin currents, whereas large Rashba effect at Ge(111) surfaces covered with heavy metals could generate spin-polarized currents. The Rashba spin splitting can actually be as large as hundreds of meV. Here we show a giant spin-to-charge conversion in metallic states at the Fe/Ge(111) interface due to the Rashba coupling. We generate very large charge currents by direct spin pumping into the interface states from 20 K to room temperature. The presence of these metallic states at the Fe/Ge(111) interface is demonstrated by first-principles electronic structure calculations. By this, we demonstrate how to take advantage of the spin-orbit coupling for the development of the spin field-effect transistor.
电子自旋和动量之间的自旋轨道耦合允许自旋产生、检测和控制。因此，它实现了自旋场效应晶体管的三个基本功能。然而，体锗中的自旋霍尔效应太弱，无法产生自旋电流，而重金属覆盖的 Ge(111)表面的大拉什巴效应可以产生自旋极化电流。拉什巴自旋分裂实际上可以大到数百毫伏特。在这里，我们展示了由于拉什巴耦合，Fe/Ge(111)界面的金属态中的巨大自旋到电荷转换。我们通过直接从 20 K 到室温将自旋泵入界面态，产生了非常大的电荷电流。Fe/Ge(111)界面处这些金属态的存在通过第一性原理电子结构计算得到了证明。通过这种方式，我们展示了如何利用自旋轨道耦合来开发自旋场效应晶体管。
