Berlin 2018 – scientific programme
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MM: Fachverband Metall- und Materialphysik
MM 47: Poster Session II
MM 47.23: Poster
Wednesday, March 14, 2018, 18:30–19:45, Poster C
Cluster expansions with CELL: applications to simple and complex alloys — •Maria Troppenz1, Santiago Rigamonti1, Martin Kuban1, and Claudia Draxl1,2 — 1Humboldt-Universität zu Berlin — 2Fritz-Haber Institut
The newly released python package CELL [1] allows for building accurate cluster expansion (CE) models. While available CE codes can tackle only small parent cells (e.g. fcc), CELL is specially suitable for studying complex alloys with large parent cells, for which a full enumeration of structures can’t be performed. In this work, we show several applications of CELL to surface and bulk alloys, ranging from simple alloys with a small parent cell, as e.g. SiGe bulk and the surface alloy AlxNa1-x/Al(100), to highly complex structures, as e.g. the thermoelectric clathrates Ba8AlxSi46-x [2] and Ba8NixGe46-x-yy with 54 atoms in the parent cell. CELL implements features like Wang-Landau method and Monte-Carlo simulations. Employing them, we could discover the thermodynamic signatures of an order-disorder transition driving an insulator-to-metal transition for Ba8Al16Si30.
[1] S. Rigamonti, M. Troppenz, M. Kuban, A. Huebner, C. Sutton, L. Ghiringhelli, M. Stournara, M. Scheffler, and C. Draxl. CELL: python package for cluster expansions with large parent cells. In preparation.
[2] M. Troppenz, S. Rigamonti, and C. Draxl, Chem. Mater. 29, 2414 (2017).