1. Giant Seebeck effect across the field-induced metal-insulator transition of InAs
- Author
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Alexandre Jaoui, Gabriel Seyfarth, Carl Willem Rischau, Steffen Wiedmann, Siham Benhabib, Cyril Proust, Kamran Behnia, and Benoît Fauqué
- Subjects
Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Atomic physics. Constitution and properties of matter ,QC170-197 - Abstract
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.
- Published
- 2020
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