First-principles anharmonic vibrational study of the structure of calcium silicate perovskite under lower mantle conditions
ArXiv 1902.03828 (2019)
First-principles anharmonic vibrational study of the structure of calcium silicate perovskite under lower mantle conditions
Physical Review B American Physical Society (APS) 99:6 (2019) 064101
Abstract:
Calcium silicate perovskite (CaSiO3) is one of the major mineral components of the lower mantle, but has been the subject of relatively little work compared to the more abundant Mg-based materials. One of the major problems related to CaSiO3 that is still the subject of research is its crystal structure under lower mantle conditions – a cubic Pm¯3m structure is accepted in general, but some have suggested that lower-symmetry structures may be relevant. In this work, we use a fully first principles vibrational self-consistent field (VSCF) method to perform high accuracy anharmonic vibrational calculations on several candidate structures at a variety of points along the geotherm near the base of the lower mantle, in order to investigate the stability of the cubic structure and related distorted structures. Our results show that the cubic structure is the most stable throughout the lower mantle, and that this result is robust against the effects of thermal expansion.Evolution of the low-temperature Fermi surface of superconducting FeSe1−xSx across a nematic phase transition
Nature npj Quantum Materials Springer Nature 4:1 (2019) 2
Optimization of superconducting properties of the stoichiometric CaKFe4As4
University of Oxford (2019)