Topology of the Fermi surfaces of group V crystalline polymorphs and optical response in the amorphous-crystalline and sphalerite-rocksalt phase pairs of GeTe phase change material

Evgeny A. Plekhanov,1,2 Andrei L. Tchougréeff2,3,4

1 King's College London, Theory and Simulation of Condensed Matter (TSCM), The Strand, London WC2R 2LS, United Kingdom 2 Independent University of Moscow, Moscow, Russia 3A.N. Frumkin Institute of Physical Chemistry and Electrochemistry of RAS, Moscow, Russia 4Institute of inorganic chemistry RWTH - Aachen University, Aachen, Germany


Despite large amount of the theoretical and experimental work performed so far the search of Phase Changing Materials (PCM) is done with use of numerical modeling without having clear theoretical guidelines. We report here a comparison of dynamic dielectric function of sphalerite (ZnS), CsCl, and rocksalt (halite, NaCl) phases of the binary AIVBVI PCM exemplified by the well known GeTe prototype compound with experimental data and supply some theoretical explanation to the observed behavior based on topological properties of the Fermi surfaces of the corresponding band structures. By this we arrive to a qualitative rather than purely numeric guidance throughout possible search of the variable optical properties of the AIVBVI binaries.