III-V semiconductors have been intensively studied with the goal of realizing metal-oxide-semiconductor field-effect transistors (MOSFETs) with high mobility, a high on-off ratio, and low power consumption as next-generation transistors designed to replace current Si technology. Of these semiconductors, a narrow band-gap semiconductor InAs has strong Rashba spin-orbit interaction, thus making it advantageous in terms of both high field-effect transistor (FET) performance and efficient spin control. Here we report a high-performance InAs nanowire MOSFET with a gate-all-around (GAA) structure, where we simultaneously control the spin precession using the Rashba interaction. Our FET has a high on-off ratio (104~106) and a high field-effect mobility (1200 cm2/Vs) and both values are comparable to those of previously reported nanowire FETs. Simultaneously, GAA geometry combined with high- κ dielectric enables the creation of a large and uniform coaxial electric field (>107 V/m), thereby achieving highly controllable Rashba coupling (1 × 10−11 eVm within a gate-voltage swing of 1 V), i.e. an operation voltage one order of magnitude smaller than those of back-gated nanowire MOSFETs. Our demonstration of high FET performance and spin controllability offers a new way of realizing low-power consumption nanoscale spin MOSFETs.

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We demonstrate experimentally that graphene quantum capacitance $C_{\mathrm{q}}$ can have a strong impact on transport spectroscopy through the interplay with nearby charge reservoirs. The effect is elucidated in a field-effect-gated epitaxial graphene device, in which interface states serve as charge reservoirs. The Fermi-level dependence of $C_{\mathrm{q}}$ is manifested as an unusual parabolic gate voltage ($V_{\mathrm{g}}$) dependence of the carrier density, centered on the Dirac point. Consequently, in high magnetic fields $B$, the spectroscopy of longitudinal resistance ($R_{xx}$) vs. $V_{\mathrm{g}}$ represents the structure of the unequally spaced relativistic graphene Landau levels (LLs). $R_{xx}$ mapping vs. $V_{\mathrm{g}}$ and $B$ thus reveals the vital role of the zero-energy LL on the development of the anomalously wide $\nu=2$ quantum Hall state.Comment: 9 pages, 6 figure

Conductivity of the metallic dangling-bond state of adatoms on Si͑111͒7 ϫ 7 clean surface was determined through passivation of the only electrical channel by ϳ0.1 monolayer Na adsorption. Through systematic measurements of electron transport and photoemission spectroscopy during the Na deposition, Si͑111͒7 ϫ 7 was found to exhibit a metal-to-insulator transition. The decrease in conductivity through the transition, which is attributed to the conductivity of the dangling-bond state, was 2-4 ⍀ −1 ᮀ −1. The value is smaller than the two-dimensional Ioffe-Regel limit and the mean-free path is too short to apply the Boltzmann picture.

Electrical tuning of spin–orbit interaction (SOI) is important for spintronics. Here we report that InSb nanowire with a nearby back gate structure enables efficient tuning of the Rashba SOI with small gate voltage. Consequently, the Rashba coupling parameter is larger than those obtained for various previously reported III–V nanowire devices. Our findings demonstrate that InSb nanowire with this back gate structure will provide prominent and easy-to-use devices in the fields of spintronics and spin–orbitronics.