Abstract
We report Shubnikov-de Haas and Hall measurements conducted on n-type modulation-doped Si/Si1-xGex heterostructures grown on relaxed Si1-xGex buffer layers. Hall mobilities up to 174 700 cm2/V s at T=0.35 K are achieved. We observe the lifting of both the spin and the valley degeneracies at rather low magnetic fields and well-defined quantum Hall plateaus at integer filling factors. The single-particle relaxation times τs are of the order of 1 ps for all samples investigated. Assuming an effective transport mass of 0.19m0 for the electrons in the lowest, twofold-degenerate Si conduction band, the transport times τt exceed τs by more than an order of magnitude. This result clearly indicates that long-range impurity scattering is the dominant scattering mechanism in high-quality Si/Si1-xGex heterostructures.
Original language | English |
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Pages (from-to) | 4344-4347 |
Number of pages | 4 |
Journal | Physical Review B |
Volume | 46 |
Issue number | 7 |
DOIs | |
State | Published - 1992 |