Akola J, Beuneu B, Jones R O, Jóvári P, Kaban I, Kolář J, Voleská I, Wágner T
Department of Physics, Tampere University of Technology, PO Box 692, FI-33101 Tampere, Finland. COMP Centre of Excellence, Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland.
J Phys Condens Matter. 2015 Dec 9;27(48):485304. doi: 10.1088/0953-8984/27/48/485304. Epub 2015 Nov 16.
Density functional/molecular dynamics simulations have been performed to determine structural and other properties of amorphous Ag/Ge/S and Ge/S alloys. In the former, the calculations have been combined with experimental data (x-ray and neutron diffraction, extended x-ray absorption fine structure). Ag/Ge/As alloys have high ionic conductivity and are among the most promising candidates for future memristor technology. We find excellent agreement between the experimental results and large-scale (500 atoms) simulations in Ag/Ge/S, and we compare and contrast the structures of Ge/S and Ag/Ge/S. The calculated electronic structures, vibrational densities of states, ionic mobilities, and cavity distributions of the amorphous materials are discussed and compared with data on crystalline phases where available. The high mobility of Ag in solid state electrolyte applications is related to the presence of cavities and can occur via jumps to a neighbouring vacant site.
