Experimental study on magnetoresistance phenomena in n-type Si/SiGe quantum wires
The resistance of a quasi-ballistic wire fabricated in a high-mobility n-type Si/SiGe heterostructure is studied as a function of magnetic field in the temperature range 0.1 K-4.2 K. The wire has a length of 10 µm and a nominal width of 400 nm. When the magnetic field is increased from 0 T to 10 T we observe weak localization, reproducible resistance fluctuations and Shubnikov-de Haas oscillations. The various effects are superimposed on a background resistance showing the influence of diffuse sidewall scattering. All these effects are separated and analysed to give a quantitative and consistent picture of the electron transport. The magnitude of the various measured transport parameters indicates that the electron transport is quasi-ballistic. Size effects due to the influence of the confining boundary potential are observed and accounted for in the theoretical descriptions.