Anisotropic magnetoconductance of a InAs nanowire: Angle-dependent suppression of one-dimensional weak localization

The magnetoconductance of an InAs nanowire is investigated with respect to the relative orientation between external magnetic field and the nanowire axis. It is found that both the perpendicular and the parallel magnetic fields induce a positive magnetoconductance. Yet the parallel magnetic field induced longitudinal magnetoconductance has a smaller magnitude. This anisotropic magnetotransport phenomenon is studied as a function of temperature, magnetic field strength, and at an arbitrary angle between the magnetic field and the nanowire. We show that the observed effect is in quantitative agreement with the suppression of one-dimensional weak localization.

Figure 1

(Color online) Dependence of conductance $G$ on gate voltage of an InAs nanowire at temperature $T=40$, 30, 20, 10, and 5 K. Nanowire diameter is 20 nm. The top inset is a schematic of the nanowire device. The scanning electron microscope image of the device is shown as the bottom inset. The scale bar is $1\mu \text{m}$.

Figure 2

(Color online) (a) InAs nanowire conductance vs magnetic field at temperature $T=40$, 30, 20, 10, and 5 K in $B_{\perp }$ (filled symbols) or $B_{\parallel }$ (open symbols). The gate voltage $V_g=0\text{V}$. Solid curves show the best fits to 1D weak-localization theory. (b) The electron phase-coherence length $L_{\phi }$ and Drude conductance $G_0$ plotted as a function of temperature. $L_{\phi }$ and $G_0$ are obtained by fitting the low-field $G\left(B_{\perp }\right)$ or $G\left(B_{\parallel }\right)$ data to 1D weak-localization theory.

Figure 3

(Color online) (a) Schematic of rotating a nanowire with diameter $w$ in magnetic field $B$. Rotation angle $\theta$ is defined to be the angle between magnetic field and the cross section of nanowire. (b) Rotation-angle dependence of an InAs nanowire conductance at $V_g=0\text{V}$ and $T=40$, 30, 20, 10, and 5 K. Solid curves are the fits to Eq. (2).