High-pressure structures and metallization of sodium chloride
State Key Lab of Superhard Materials, Jilin University - Changchun 130012, PRC
Received: 31 July 2012
Accepted: 26 September 2012
Sodium chloride (NaCl) is known as salt and an ionic insulator at ambient conditions. The high-pressure structures of NaCl have been extensively explored through a particle swarm structural search at zero temperature and pressure range of 0–800 GPa. In addition to the known low-pressure insulating phases, we find three novel orthorhombic high-pressure structures: oC8 (stable at 322–645 GPa), oI8 (stable at 645–683 GPa), and oP16 (stable at above 683 GPa). The oC8 structure can be metallized via band-gap closure under high pressure, while both oI8 and oP16 are metallic in their stable pressure ranges. Intriguingly, our predicted metallic high-pressure phases of NaCl retain predominant ionic behaviors. The peculiar conductive behaviors can be attributed to the extended anion sublattice.
PACS: 62.50.-p – High-pressure effects in solids and liquids / 61.50.-f – Structure of bulk crystals / 71.20.-b – Electron density of states and band structure of crystalline solids
© EPLA, 2012