Giant Seebeck effect across the field-induced metal-insulator transition of InAs
Abstract Lightly doped III–V semiconductor InAs is a dilute metal, which can be pushed beyond its extreme quantum limit upon the application of a modest magnetic field. In this regime, a Mott-Anderson metal–insulator transition, triggered by the magnetic field, leads to a depletion of carrier concen...
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| Autores principales: | , , , , , , , |
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| Formato: | article |
| Lenguaje: | EN |
| Publicado: |
Nature Portfolio
2020
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| Materias: | |
| Acceso en línea: | https://doaj.org/article/5a18d7ae74a14aeab76deba7e45838a9 |
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| Sumario: | Abstract Lightly doped III–V semiconductor InAs is a dilute metal, which can be pushed beyond its extreme quantum limit upon the application of a modest magnetic field. In this regime, a Mott-Anderson metal–insulator transition, triggered by the magnetic field, leads to a depletion of carrier concentration by more than one order of magnitude. Here, we show that this transition is accompanied by a 200-fold enhancement of the Seebeck coefficient, which becomes as large as 11.3 mV K−1 $$\approx 130\frac{{k}_{B}}{e}$$ ≈ 130 k B e at T = 8 K and B = 29 T. We find that the magnitude of this signal depends on sample dimensions and conclude that it is caused by phonon drag, resulting from a large difference between the scattering time of phonons (which are almost ballistic) and electrons (which are almost localized in the insulating state). Our results reveal a path to distinguish between possible sources of large thermoelectric response in other low-density systems pushed beyond the quantum limit. |
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