The mechanism of electrical conduction in glassy semiconductors

• 成果类型: Article
• 署名作者: Kurnosov, Arkady; Lubchenko, Vassiliy
• 署名单位: University of Houston System; University of Houston; Wesleyan University; University of Houston System; University of Houston; University of Houston System; University of Houston
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13157
• DOI: 10.1073/pnas.2414650122
• 发表日期: 2025-03-11
• 关键词: supercooled liquids; temperature; transport; STATES; photoluminescence; TRANSITION; DYNAMICS; solitons; defects; barrier

摘要

We argue that the dominant charge carrier in glassy semiconducting alloys is a compound particle in the form of an electron or hole bound to an intimate pair of topological lattice defects; the particle is similar to the polaron solution of the Su-Schrieffer-Heeger Hamiltonian. The spatial component of the density of states for these special polarons is determined by the length scale of spatial modulation of electronegativity caused by a separate set of standalone topological defects. The latter length scale is fixed by the cooperativity size for structural relaxation; the size is largely independent of temperature in the glass but above melting, it decreases with temperature. Thus we predict that the temperature dependence of the electrical conductivity should exhibit a jump in the slope near the glass transition; the size of the jump is predicted to increase with the fragility of the melt. The predicted values of the jump and of the conductivity itself are consistent with experiment.