Abstract:
High pressure effects on transition metal compounds have been explored using a suitable potential model. A theoretical study of high pressure phase transition and elastic behaviour in transition metal compounds using a three body interaction (TBI) potential caused by the electron shell deformation of the overlapping ion is carried out. Being a very hard material transition metal compounds show a phase transition at very high pressure ~485GPa.We applied the TBPM to study this transition in Titanium compounds. TiC, TiN show phase transition from the relatively open NaCl structure into the more dense CsCl atomic arrangement. The phase transition pressure predicted from our model is closer to the phase transition pressure, predicted by Ahuja et, al [Phys.Rev.B.53,3072,1996]
Under high pressure TiO and TiN undergo phase transition from B1 (rocksalt) to B2 (CsCl) structure associated with a sudden collapse in volume showing first order phase transition. Application of pressure on materials, thus provides thermodynamic states from condensed matter region to extreme high density screened coulomb limit. The pressure volume temperature relationship (PVT) termed the equation of state (EOS) is an important output of high pressure experiment providing meaningful signatures of physical and chemical phenomena under high pressure.
