3.4.1 Hydrostatic Strain

Expression (3.31) gives the hydrostatic shift of the mean energy of both $ X$ and $ L$ valleys:

$\displaystyle \Delta\epsilon^{X,L}_{c,av}=\biggl(\Xi_{d}^{X,L}+\frac{1}{3}\Xi_{u}^{X,L}\biggr)(\varepsilon_{11}+\varepsilon_{22}+\varepsilon_{33}).$ (3.58)

Note that the deformation potentials for $ X$ and $ L$ valleys are different. S. Smirnov: