Metal-Nonmetal Transition in Liquid Alkali Metal-Alkalihalide Melts: Electrical Conductivity and Optical Reflectivity Study

The electronic structure of metal-molten salt solutions: A tight-binding approach

“…3 and compared to experimental values measured on the K-KCl and the K-KBr system. 6,7 EMT conductivity values trivially coincide with the experimental data at xϭ0 and xϭ1. In general, the hyperbolic form characteristic of a percolationlike crossover fails to represent the much smoother experimental curve.…”

“…The change of the sign of the temperature dependence of the electronic conductivity, d e /dT, indicates a nonmetal→metal transition at xӍ0.2 in K-KCl. 7 Due to the Fermionic character of electrons even at temperatures of 10 3 K, typical for molten salts, it is solely the localized or extended nature of eigenstates around the Fermi level and not-as often claimed-the percolation of the entire charge density that determines the point of the nonmetalmetal transition. The latter rather ambiguously defined feature may only serve as a lower boundary of the NMMT, approaching the point of the Anderson transition from the nonmetallic side.…”

Nonmetal-metal transition in metal–molten-salt solutions

“…[2][3][4][5][6][7][8][9][10][11] Low concentrations of excess electrons are localized. 25 In principle different configurations are possible: neutral alkali atoms, multisite localized states, and F centers.…”

“…4,8,10,18,27 The observed infrared dielectric anomaly 6 could indicate that the NM-M transition may occur at a metal concentration as low as xӍ0.1; however, this transition should really appear through a divergence of the static dielectric constant. 28 More probably 18 the anomaly simply indicates the appearance of sizable metallic clusters, the system as a whole still being in a nonmetallic state.…”

“…Among the systems where the NM-M transition has been observed, metal-molten-salt solutions of the type M x (M X) 1Ϫx have been studied extensively through experiments, [2][3][4][5][6][7][8][9][10][11] computer simulations, [12][13][14][15] and theory. 1,[16][17][18] The alkali metals dissolve in molten alkali halides to form true solutions.…”