Orientation of Metastable EL2 under Uniaxial Stress

Results of electrical resistivity and Hall measurements of n-type GaAs under uniaxial stress along [111] direction performed at low temperature are presented. Alter the transformation of the EL2 defect into its metastable configuration, a stress-induced increase in electrical resistivity related to the capture of electrons by the acceptor state of the metastable EL2([EL2*]$\text{}_{-}\text{}_{/}\text{}_{0}$) was observed. It was found that the stress-induced increase in resistivity depended on the method of EL2-photoquenching. The observed effects are explained as the reorientation of EL2* centers in the crystal. The stress coefficients of the triple degenerate and the single degenerate sublevels of the [EL2*]$\text{}_{-}\text{}_{/}\text{}_{0}$ are found to be equal to -17 meV/GPa and -41 meV/GPa.