Theoretical study of pressure effect on the dislocation core properties in semiconductors

The effect of an applied pressure on the core of screw dislocations in semiconductors such as Si, beta-SiC, and diamond has been investigated by carrying out tight-binding and first-principles calculations of the variations in dislocation core energies and in energy barriers for dislocation translation. Pressure is found to have a sizable effect and can lead to either decreases or increases in the latter quantities. It is also shown that it is advisable to take into account all pressure-dependent parameters for accurately determining this effect. Nevertheless, we found that for the investigated materials, the effect of pressure was not strong enough to induce structural transformations of the dislocation core. The mobility of the cores was also found to be dependent on pressure, which tends to increase or decrease the energy barriers according to the direction of the dislocation displacement.