Project C4

Spin Properties of Isotope Clean Si/Ge Nanostructures

PIs: Prof. G. Abstreiter, Dr. D. Bougeard

The objectives of this project are:

  1. the realization of top gated quantum dots and single electron transistors based on two dimensional carrier gases in nuclear spin free SiGe environment (Figure 1).

  2. the exploration of the possibility of electrical g-factor switching in double quantum well structures.

  3. the optimization of MBE growth of high quality isotope engineered Si/SiGe and Ge/SiGe heterostructures as well as the fabrication of test structures for the basic understanding of spin related phenomena in Si/Ge structures with and without P doping atoms.

  4. to understand spin relaxation and decoherence mechanisms of electrons and holes in two dimensional SiGe carrier gases and the influence of nuclear spins on these mechanisms.

We currently focus on transport and spin properties of strained Si/SiGe (double) quantum wells. These activities involve the design of isotopically engineered structures and the tuning of g-factors in heterostructures. Characterisation techniques include x-ray diffraction, optical spectroscopy and magneto-transport measurements. Spin resonance is investigated in close collaboration with project C3.


Figure 1: Schematic of an electrostatically defined double quantum dot in a nuclear spin free environment. The electrons reside in the nuclear spin free strained 28Si layer and are controlled via Schottky top gates.