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-ty pe Si/SiGe heterostructure is studied as a function of magnetic field in th e temperature range 0.1 K4.2 K. The wire has a length of 10 mu m and a nomi nal width of 400 nm. When the magnetic field is increased from 0 T to 10 T we observe weak localization, reproducible resistance fluctuations and Shub nikov-de Haas oscillations. The various effects an superimposed on a backgr ound resistance showing the influence of diffuse sidewall scattering. All t hese effects are separated and analysed to give a quantitative and consiste nt picture of the electron transport. The magnitude of the various measured transport parameters indicates that the electron transport is quasi-ballis tic. Size effects due to the influence of the confining boundary potential are observed and accounted fur in the theoretical descriptions.