Photoluminescence Spectra and Unusual Temperature Shift of Zero-Phonon Emission Line of V3+ in SrTiO3

The paper presents the first observation of photoluminescence spectra of V 3+ impurity in SrTiO 3 . The broad band of the observed emission is located in the near IR region and at low temperatures consists of a pronounced zero-phonon line (ZPL) with a maximum at 1157.1 nm (8642 cm –1 ) at 77 K and developed vibronic sidebands extending to 1450nm. The observed ZPL is associated with an intracenter 1 T 2 g → 3 T 1 g or a closely located 1 E g → 3 T 1 g emission transition in V 3+ (3 d 2 ) ions replacing Ti 4+ ions. It was found that the temperature shift of zero-phonon line is unusually large and its frequency decreases upon lowering the temperature. The local configuration instability of V 3+ ions in the 3 T 1 g ground state caused by soft TO 1 temperature-dependent phonon mode present in SrTiO 3 is considered as a possible source of the observed unusual temperature shift.