Raman scattering investigations of Jahn-Teller induced phase transitions in TmAsO4and TmVO4

Abstract
The low temperature Jahn-Teller induced phase transitions in TmAsO4 at 6.0K and in TmVO4 at 2.1.K have been investigated by means of Raman scattering. Phonon and electronic excitations have been observed in magnetic fields of up to 50kG. The results show that the Jahn-Teller distortion may be removed by application of a magnetic field and that the coupling of the Tm3+ ions to acoustic phonons is stronger than to optic phonons. The implications of this coupling are discussed.