Electronic states of alkali-electro-sodalite under pressure

Insulator-Metal transition of a bcc electron lattice in the alumino-silicate cage compound, A 8 (SiAlO 4 ) 6 , (A is Na or K) is investigated under high pressure. ESR has been measured to obtain the spin susceptibility that gives the Neel T N and the Weiss Θ temperatures. They were analysed to give the exchange interactions J 1 and J 2 through the windows with a hexagonal and a square shapes. Finally, the transfer energies t 1 and t 2 through these windows were shown to follow exponential functions of the pressure with different characteristic pressures, giving rise to a comprehensive interpretation of the pressure dependence of T N and Θ.