First-principles calculation of alloy scattering in GexSi1-x
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Date
2006-09
Authors
Murphy-Armando, Felipe
Fahy, Stephen B.
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Publisher
American Physical Society
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Abstract
First-principles electronic structure methods are used to find the rates of intravalley and intervalley n-type carrier scattering due to alloy disorder in Si1-xGex alloys. The required alloy scattering matrix elements are calculated from the energy splitting of nearly degenerate Bloch states which arises when one average host atom is replaced by a Ge or Si atom in supercells containing up to 128 atoms. Scattering parameters for all relevant Delta and L intravalley and intervalley alloy scattering are calculated. Atomic relaxation is found to have a substantial effect on the scattering parameters. f-type intervalley scattering between Delta valleys is found to be comparable to other scattering channels. The n-type carrier mobility, calculated from the scattering rate using the Boltzmann transport equation in the relaxation time approximation, is in excellent agreement with experiments on bulk, unstrained alloys.
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Keywords
SixGe1-x alloys , Electron theory , Mobility , Pseudopotentials , Semiconductors , Transport , Systems , Devices , Model , Si
Citation
Murphy-Armando, F. and Fahy, S. B. (2006) 'First-principles calculation of alloy scattering in GexSi1-x'. Physical Review Letters, 97 (9), 096606. doi:10.1103/PhysRevLett.97.096606
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© 2006 The American Physical Society