TY - JOUR
T1 - Predicted complex lithium phases at terapascal pressures
AU - Whaley-Baldwin, Jack
AU - Martinez-Canales, Miguel
AU - Pickard, Chris J.
N1 - Publisher Copyright:
© 2025 authors. Published by the American Physical Society.
PY - 2025/4/2
Y1 - 2025/4/2
N2 - We investigate the pressure-temperature (p-T) phase diagram of elemental lithium (Li) up to multiterapascal (TPa) pressures using ab initio random structure search (AIRSS) and density functional theory (DFT). At zero temperature, beyond the high-pressure Fd3¯m diamond structure already predicted in previous studies, we find 11 solid-state phase transitions to structures of greatly varying complexity. The full p-T dependence of the phase boundaries are computed within the vibrational quasi-harmonic approximation (QHA), and the solid-liquid melting line is calculated using two different ab initio molecular dynamics simulation methods (heat-until-melt and the Z method). Notably, between 39.1 and 55.7 TPa, Li adopts an elaborate monoclinic structure with 46 atoms in the primitive unit cell, and between 71.9 and 103 TPa, an incommensurate host-guest phase of the Ba-IV type. We find that Li, hitherto predicted to be an electride at TPa pressures, abruptly loses its electride character above 16 TPa, reverting back to normal metallic behavior with a corresponding rise in the Fermi-level electronic density of states (eDOS) and broadening of the electronic bands.
AB - We investigate the pressure-temperature (p-T) phase diagram of elemental lithium (Li) up to multiterapascal (TPa) pressures using ab initio random structure search (AIRSS) and density functional theory (DFT). At zero temperature, beyond the high-pressure Fd3¯m diamond structure already predicted in previous studies, we find 11 solid-state phase transitions to structures of greatly varying complexity. The full p-T dependence of the phase boundaries are computed within the vibrational quasi-harmonic approximation (QHA), and the solid-liquid melting line is calculated using two different ab initio molecular dynamics simulation methods (heat-until-melt and the Z method). Notably, between 39.1 and 55.7 TPa, Li adopts an elaborate monoclinic structure with 46 atoms in the primitive unit cell, and between 71.9 and 103 TPa, an incommensurate host-guest phase of the Ba-IV type. We find that Li, hitherto predicted to be an electride at TPa pressures, abruptly loses its electride character above 16 TPa, reverting back to normal metallic behavior with a corresponding rise in the Fermi-level electronic density of states (eDOS) and broadening of the electronic bands.
UR - http://www.scopus.com/inward/record.url?scp=105001704647&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.111.134105
DO - 10.1103/PhysRevB.111.134105
M3 - Article
AN - SCOPUS:105001704647
SN - 2469-9950
VL - 111
SP - 1
EP - 7
JO - Physical Review B
JF - Physical Review B
IS - 13
M1 - 134105
ER -