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Low temperature terahertz spectroscopy of n-InSb through a magnetic field driven metal-insulator transition

X. P. A. Gao·J. Y. Sohn·S. A. Crooker
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Abstract

We use fiber-coupled photoconductive emitters and detectors to perform terahertz (THz) spectroscopy of lightly-doped n-InSb directly in the cryogenic (1.5 K) bore of a high-field superconducting magnet. We measure transmission spectra from 0.1-1.1 THz as the sample is driven through a metal-insulator transition (MIT) by applied magnetic field. In the low-field metallic state, the data directly reveal the plasma edge and magneto-plasmon modes. With increasing field, a surprisingly broad band (0.3-0.8 THz) of low transmission appears at the onset of the MIT. This band subsequently collapses and evolves into the sharp 1s -> 2p- transition of electrons `frozen' onto isolated donors in the insulating state.

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X. P. A. Gao, J. Y. Sohn, S. A. Crooker. 2006-05-24. Low temperature terahertz spectroscopy of n-InSb through a magnetic field driven metal-insulator transition. https://doi.org/10.1063/1.2356105

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