Advanced Device Laboratory , RIKEN , 2-1 Hirosawa , Wako, Saitama 351-0198 , Japan.
School of Physical Science and Electronics , Central South University , Changsha 410083 , China.
Nano Lett. 2018 Oct 10;18(10):6144-6149. doi: 10.1021/acs.nanolett.8b01799. Epub 2018 Sep 19.
Helical states, a prerequisite for the engineering of Majorana zero modes in solid-state systems, have recently been reported in the conduction band of III-V nanowires (NWs) subject to strong Rashba spin-orbit interaction. We report the observation of re-entrant conductance features consistent with the presence of helical hole states in multiple conduction modes of a Ge/Si core/shell NW. The Ge/Si system has several potential advantages over electron systems such as longer spin coherence time due to weaker coupling to nuclear spins and the possibility of isotope-purified materials for nuclear spin-free devices. We derive the Landé g factor of 3.6 from magneto-transport measurements, comparable to theoretical predictions and significantly larger when compared with that in strongly confined quantum dots. The spin-orbit energy is evaluated as ∼2.1 meV, on par with values in III-V NWs, showing good agreement with previous theoretical predictions and weak antilocalization measurements.
螺旋态是在固态系统中工程化马约拉纳零模的前提条件，最近在受强拉什巴自旋轨道相互作用影响的 III-V 纳米线（NWs）的导带中得到了报道。我们报告了在 Ge/Si 核/壳 NW 的多个导带模式中存在与螺旋空穴态一致的再进入电导特征的观察结果。与电子系统相比，Ge/Si 系统具有几个潜在的优势，例如由于与核自旋的耦合较弱，自旋相干时间更长，以及有可能获得用于无核自旋器件的同位素纯化材料。我们从磁输运测量中得出 g 因子为 3.6，与理论预测相当，与强受限量子点中的 g 因子相比显著增大。自旋轨道能量评估为~2.1meV，与 III-V NWs 的数值相当，与之前的理论预测和弱反局域测量结果吻合良好。
