Giant Seebeck effect across the field-induced metal-insulator transition of InAs

Alexandre Jaoui; Gabriel Seyfarth; Carl Willem Rischau; Steffen Wiedmann; Siham Benhabib; Cyril Proust; Kamran Behnia; Benoît Fauqué

arXiv · 2008.06356

Giant Seebeck effect across the field-induced metal-insulator transition of InAs

Alexandre Jaoui·Gabriel Seyfarth·Carl Willem Rischau·Steffen Wiedmann·Siham Benhabib·Cyril Proust·Kamran Behnia·Benoît Fauqué

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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 two-hundred-fold enhancement of the Seebeck coefficient which becomes as large as 11.3mV.K$^{-1}\approx 130\frac{k_B}{e}$ at T=8K and B=29T. 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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Alexandre Jaoui, Gabriel Seyfarth, Carl Willem Rischau, Steffen Wiedmann, Siham Benhabib, Cyril Proust, Kamran Behnia, Benoît Fauqué. 2020-08-14. Giant Seebeck effect across the field-induced metal-insulator transition of InAs. https://arxiv.org/abs/2008.06356

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