Guest Seminar - Novel nanometric phases of the monochalcogenides: Theory meets experiment - Prof. Guy Makov

Abstract

Tin and germanium monochalcogenides M(=Ge,Sn)X(=S,Se) are earth-abundant, low-toxicity materials with strong potential for energy and optoelectronic applications. Recently, novel nanoscale phases with attractive new functionalities have been discovered. Using ab initio modelling, we uncover their atomic structures and predict their physical and chemical properties. 
The key mechanisms that stabilize these metastable phases—including size confinement, ligand binding, impurities, and substrates—are explored by modelling surface energies, ligand adsorption, impurity and substrate effects. Direct comparison with controlled experiments reveals how synthesis conditions selectively stabilize these phases.
We show that these nanophases belong to a broader family of metastable bulk structures, mapped using genetic algorithms and driven by lone-pair activity analogous to Peierls’ instabilities in p-block elements. Our results demonstrate a predictive, ab initio route to the targeted synthesis of metastable phases.

Bio

Guy Makov is a professor at the department of Materials Engineering at Ben-Gurion University of the Negev. Scientific education includes B.Sc. in Chemistry, Ph.D. in Chemical Physics from Tel Aviv University; postdocs and sabbaticals at Cambridge University, FZ Julich and King’s College London.  Guy’s research aims to predict from basic physical models the properties of materials, including electronic structure, equilibrium properties and response to mechanical deformations or irradiation.  Specific interests include radiation damage in metals, novel inorganic materials, the liquid state, phase diagrams under pressure and dislocations in metals.  Research is pursued using classical and quantum models of materials and in close collaboration with experimentalists. The Makov research group currently consists of two postdocs, five Ph.D. students and six M.Sc. students; over 35 research students have graduated from the group. Guy has published over 100 peer-reviewed research papers, which have received some 7000 citations.