Influence of Electron-electron Drag on Piezoresistance of n-Si
  Piezoresistance of n-Si is considered with due regard for inter-valley drag. It is shown that inter-valley drag gains the piezocoefficient and diminishes the mobility. In the region of nondegenerate carriers the effect of drag increases when carrier concentration rises and temperature falls. 
I.I. Boiko
cond-mat.stat-mech