Lifshitz transition in \textit{cI}16 Li at high pressures: Unfolding first-principles Fermi surfaces

The Fermi surface topology of \textit{cI}16 Li is investigated using the recently developed first-principles band structure unfolding method [1]. The resulting unfolded Fermi surfaces display a clear Lifshitz transition at 47 GPa, explaining the anomalous change of superconducting transition temperature [2]. The unfolded Fermi surfaces also reveals a more complete picture of the driving force of the \textit{cI}16 phase starting at 39 GPa [3]. In addition to the previously proposed ``nesting'' effect [3] along [1$\frac{1}{2}\frac{1}{2}$], both [100] and [$\frac{1}{2}\frac{1}{2}$0] wavevectors are found to contribute significantly to the structural instability as well, due to their large phase space, a more effective effect in 3D. We expect a wide range of applications of this Fermi surface unfolding method to the study of high pressure electronic structure.\\[4pt] [1] Wei Ku et al, Phys. Rev. Lett. {\bf 104}, 216401 (2010)\\[0pt] [2] S. Deemyad and J. S. Schilling, Phys. Rev. Lett. {\bf 91}, 167001 (2003)\\[0pt] [3] M. Hanfland et al, Nature {\bf 408}, 174 (1998)