Ballistic Spin Transport in InSb Nanowires with Strong Rashba Spin-Orbital Interaction

Abstract

Semiconductors nanowires (NWs) with strong spin-orbital interaction, like InSb and InAs nanowires, are a leading platform for realizing future computing devices, such as Datta-Das spin-transistor1 and topological-superconductor quantum computing devices2 using Majorana zero modes. Coupling nanowires to electrical spin-selective contacts, therefore, is an important step as it can, on the one hand, provide a setting to study spin transport in quantum wires, and on the other hand could enable the realization of Majorana devices that do not require an applied magnetic field, by taking advantage of the magnetic exchange interaction or spin accumulation. Here, we will discuss our measurements on InSb NW devices with iron (Fe) electrical contacts3 (see Figure 1, scanning electron microscopy picture). Conductance measurements show conductance quantization and Fabry–Pérot interference, clearly demonstrating phase-coherent and ballistic electronic transport with spin-polarized currents. Our magnetoconductance study clearly demonstrates spin injection/ transport across the NWs by the observation of hysteretic spin-valve signals (Figure 2a). Moreover, we show that electrostatic gating tunes the observed hysteretic signal and reveals a transport regime where the device acts as a spin filter (Figure 2b). *Supported primarily by the Department of Energy under Award No. DE-SC-0019274. Nanowire growth was supported by the European Research Council (ERC HELENA 617256), and the Dutch Organization for Scientific Research (NWO).