Magnetotransport of electrons in arrays of wires in Si/Si_0.7 Ge_0.3 heterostructures

Magneto transport parallel to quantum wires in Si/SiGe heterostructures was conducted in the quasi-ballistic regime. We observed magnetoresistance oscillations due to the depopulation of quasi-one dimensional sub-bands, and at low magnetic fields a well pronounced peak arising from diffuse scattering at the wire boundaries emerges. The analysis of these features yields a maximum sub-band spacing of 1 meV at a corresponding wire width of 70 nm. Electron transport perpendicular to shallow etched wires was investigated in lateral superlattices with a period of 350 nm. At magnetic fields below 0.7 T magnetotransport measurements show commensurability oscillations corresponding up to three periods of the wire grating. However, the modulated lateral potential is not purely sinusoidal, resulting in a splitting of the commensurability oscillations.