Detection of the EL2 metastability by x-ray rocking-curve measurements at low temperatures

Abstract
X-ray experiments are usually seen as a tool for studying large lattice imperfections. We present for the first time experimental evidence obtained from x-ray measurements that metastable behavior of the EL2 defect in semi-insulating GaAs can be connected with crystal lattice relaxation. New unexpected results showing change of the lattice state while cooling semi-insulating GaAs samples in darkness are also reported.