Fluctuation-dissipation in thermoelectric sensors

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Date
2023
Authors
Tran, N.A.M.
Dutt, A.S.
Pulumati, N.B.
Reith, H.
Hu, A.
Dumont, A.
Nielsch, K.
Tremblay, A.-M.S.
Schierning, G.
Reulet, B.
Volume
141
Issue
2
Journal
Europhysics Letters
Series Titel
Book Title
Publisher
Les-Ulis : EDP Science
Abstract

Thermoelectric materials exhibit correlated transport of charge and heat. The Johnson-Nyquist noise formula 4k B T R for the spectral density of voltage fluctuations accounts for fluctuations associated solely with Ohmic dissipation. Applying the fluctuation-dissipation theorem, we generalize the Johnson-Nyquist formula for thermoelectrics, finding an enhanced voltage fluctuation spectral density 4k B T R(1 + Z D T) at frequencies below a thermal cut-off frequency f T, where Z D T is the dimensionless thermoelectric device figure of merit. The origin of the enhancement in voltage noise is thermoelectric coupling of temperature fluctuations. We use a wideband , integrated thermoelectric micro-device to experimentally confirm our findings. Measuring the Z D T enhanced voltage noise, we experimentally resolve temperature fluctuations with a root mean square amplitude of at a mean temperature of 295 K. We find that thermoelectric devices can be used for thermometry with sufficient resolution to measure the fundamental temperature fluctuations described by the fluctuation-dissipation theorem.

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CC BY 4.0 Unported