The mechanism of electrical conduction in glassy semiconductors
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866915290596507648 |
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| author | Kurnosov, Arkady Lubchenko, Vassiliy |
| author_facet | Kurnosov, Arkady Lubchenko, Vassiliy |
| contents | 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. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2407_04829 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | The mechanism of electrical conduction in glassy semiconductors Kurnosov, Arkady Lubchenko, Vassiliy Mesoscale and Nanoscale Physics 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. |
| title | The mechanism of electrical conduction in glassy semiconductors |
| topic | Mesoscale and Nanoscale Physics |
| url | https://arxiv.org/abs/2407.04829 |