Strong g-Factor Anisotropy in Hole Quantum Dots Defined in Ge/Si Nanowires

Abstract

We demonstrate fully tunable single and double quantum dots in a one-dimensional hole system based on undoped Ge/Si core-shell nanowire heterostructures. The local hole density along the nanowire is controlled by applying voltages to five top gate electrodes with a periodicity of 80 nm, insulated from the wire by a 20 nm-thick HfO2 dielectric film. Low-temperature transport measurements were used to investigate the magnetic field dependence of Coulomb blockade peaks in a single quantum dot and indicate a strongly anisotropic g-factor with |gpara| = 0.60 +/- 0.03 and |gperp| < 0.12.