Bipolar Thermoelectric Josephson Engine

Fuente: arXiv
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Main Authors: Germanese, Gaia, Paolucci, Federico, Marchegiani, Giampiero, Braggio, Alessandro, Giazotto, Francesco
Format: Preprint
Published: 2022
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author Germanese, Gaia
Paolucci, Federico
Marchegiani, Giampiero
Braggio, Alessandro
Giazotto, Francesco
author_facet Germanese, Gaia
Paolucci, Federico
Marchegiani, Giampiero
Braggio, Alessandro
Giazotto, Francesco
contents Thermoelectric effects in metals are typically small due to the nearly-perfect particle-hole (PH) symmetry around their Fermi surface [1, 2]. Despite being initially considered paradoxical [3], thermophase effects [4-8] and linear thermoelectricity [9] in superconducting systems were identified only when PH symmetry is explicitly broken [10-14]. Here, we experimentally demonstrate that a superconducting tunnel junction can develop a very large bipolar thermoelectric effect in the presence of a nonlinear thermal gradient thanks to spontaneous PH symmetry breaking [15]. Our junctions show a maximum thermovoltage of $\pm150\; μ$ V at $\pm650$ mK, directly proportional to the superconducting gap. Notably, the corresponding Seebeck coefficient of $\pm300\; μ$V/K is roughly $10^5$ times larger than the one expected for a normal metal at the same temperature [16, 17]. Moreover, by integrating our junctions into a Josephson interferometer, we realize a bipolar thermoelectric Josephson engine (BTJE) [18] with phase-coherent thermopower control [19]. When connected to a generic load, the BTJE generates a phase-tunable electric power up to about 140 mW/m$^2$ at subKelvin temperatures. In addition, our device implements the prototype for a persistent thermoelectric memory cell, written or erased by current injection [20]. We expect that our findings will trigger thermoelectricity in PH symmetric systems, and will lead to a number of groundbreaking applications in superconducting electronics [21], cutting-edge quantum technologies [22-24] and sensing [25].
format Preprint
id arxiv_https___arxiv_org_abs_2202_02121
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Bipolar Thermoelectric Josephson Engine
Germanese, Gaia
Paolucci, Federico
Marchegiani, Giampiero
Braggio, Alessandro
Giazotto, Francesco
Mesoscale and Nanoscale Physics
Superconductivity
Thermoelectric effects in metals are typically small due to the nearly-perfect particle-hole (PH) symmetry around their Fermi surface [1, 2]. Despite being initially considered paradoxical [3], thermophase effects [4-8] and linear thermoelectricity [9] in superconducting systems were identified only when PH symmetry is explicitly broken [10-14]. Here, we experimentally demonstrate that a superconducting tunnel junction can develop a very large bipolar thermoelectric effect in the presence of a nonlinear thermal gradient thanks to spontaneous PH symmetry breaking [15]. Our junctions show a maximum thermovoltage of $\pm150\; μ$ V at $\pm650$ mK, directly proportional to the superconducting gap. Notably, the corresponding Seebeck coefficient of $\pm300\; μ$V/K is roughly $10^5$ times larger than the one expected for a normal metal at the same temperature [16, 17]. Moreover, by integrating our junctions into a Josephson interferometer, we realize a bipolar thermoelectric Josephson engine (BTJE) [18] with phase-coherent thermopower control [19]. When connected to a generic load, the BTJE generates a phase-tunable electric power up to about 140 mW/m$^2$ at subKelvin temperatures. In addition, our device implements the prototype for a persistent thermoelectric memory cell, written or erased by current injection [20]. We expect that our findings will trigger thermoelectricity in PH symmetric systems, and will lead to a number of groundbreaking applications in superconducting electronics [21], cutting-edge quantum technologies [22-24] and sensing [25].
title Bipolar Thermoelectric Josephson Engine
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2202.02121