Structural and electrical behavior of CeVO4 under pressure studied using x-ray diffraction and electrical resistance measurements and first principles calculations.
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Two successive structural transitions confirmed by experiment & theory: zircon--monazite I--monazite II.
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Band gap collapse and possible metallization is indicated by electrical resistance measurements and electronic structure calculations under pressure.
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Novel observation of lower bulk modulus in the high pressure phase (both by experiment and calculations) explained through structural analysis.
Abstract
Phase stability of CeVO4 under pressure has been investigated using synchrotron based angle dispersive x-ray diffraction (ADXRD), electrical resistance and first principles calculations. The results indicate that the ambient zircon structure of the compound transforms to a low symmetry monoclinic monazite phase beyond 3.8 GPa with nearly 8.6% volume discontinuity. Beyond 11 GPa, the pattern could be fitted to a similar monazite structure which is about 12.7% denser and has a much larger monoclinic beta angle. On pressure release the first monoclinic phase is recovered. The electrical resistance data shows large drop in resistance with pressure indicating substantial narrowing down of the band gap. Electronic structure calculations support these observations and suggest possible pressure induced metallization in this material.
