Matthias Brauns, Utwente

Title: G-factor anisotropy in Ge-Si core-shell nanowires
Session: Tuesday 6 October, 11:00

Abstract

G-factor anisotropy in Ge-Si core-shell nanowires

M. Brauns1, J. Ridderbos1, A. Li2, E.Bakkers2, and F.A. Zwanenburg1

1 NanoElectronics Group, MESA+ Institute for Nanotechnology, University of Twente, Drienerlolaan 5, 7522 NB Enschede, The Netherlands

2 Photonics & Semiconductor Nanophysics Group, Department of Applied Physics, TU Eindhoven, Den Dolech 2, 5612 AZ Eindhoven, The Netherlands

We grow monocrystalline and nearly defect-free Ge-Si core-shell nanowires, which we use to fabricate devices with ohmic contacts to the nanowire and local gates. The low defect density allows us to electrostatically define quantum dots of various lengths in the wires. We can control quantum dot lengths from ~50 to ~400 nm and the longer dots can be split into a double dot in a controlled way from strong to very weak interdot tunnel coupling indicating a very clean system.

In agreement with theoretical calculations in literature [1], we observe g-factors up to 8 in magnetospectroscopy measurements on quantum dots of several sizes, and also find the g-factor to be highly anisotropic reaching the maximum value when the magnetic field is perpendicular to the wire axis. These high g-factors would be useful for quantum computation applications using spin-orbit states as well as Majorana bound states.

[1] Maier F, Kloeffel C, Loss D (2013) Phys. Rev. B 87 161305.

 

 

 

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