20231110 Bipolar thermoelectricity from non-equilibrium spontaneous particle-hole symmetry broken.

Title: Bipolar thermoelectricity from non-equilibrium spontaneous particle-hole symmetry broken.
Speaker: Dr. Alessandro Braggio
Affiliation: Istituto di Nanoscienze CNR-NANO & NEST, Scuola Normale Superiore
Date and time: Nov. 10 (Fri.), 4pm

We have recently predicted[1] and demonstrated[2] the possibility of generating a new thermoelectric effect. In
particular, we predicted the bipolar thermoelectricity effect in a superconducting tunnel junction with
asymmetric gaps where the Josephson coupling is suppressed[1]. The bipolar thermoelectricity is determined by
the spontaneous particle-hole symmetry breaking determined by the non-equilibrium condition (nonlinear
thermal gradient applied to the junction) and can be even tuned by phase control[2,3]. The spontaneous
symmetry breaking clearly shows the crucial role of the interactions which are at the base of the
superconductivity. In a single-electron transistor setup, the Coulomb interaction develops the capability of gate
control of the bipolar thermoelectricity[4]. Furthermore, we will comment on a few possible applications of this
phenomenology spanning from current controlled superconducting thermoelectric memory[1], high-sensitivity
bolometers[5], bilayer-graphene nanodevices[6], bipolar thermoelectric SQUIPT[7] or even intriguing photoassisted
thermoelectric nanodevices[8].

[1] Nonlinear Thermoelectricity with Electron-Hole Symmetric Systems G. Marchegiani, A. Braggio, and F.
Giazotto Phys. Rev. Lett. 124, 106801
(2020) https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.124.106801
[2] Bipolar thermoelectric Josephson engine G Germanese, F. Paolucci, G. Marchegiani, A. Braggio, F.
Giazotto Nature Nanotech. 171084 (2022)[Patented] https://www.nature.com/articles/s41565-022-01208-y
[3] Phase Control of Bipolar Thermoelectricity in Josephson Tunnel Junctions G, Germanese, F. Paolucci, G.
Marchegiani, A. Braggio, F. Giazotto
Phys. Rev. Applied 19, 014074 (2023) https://doi.org/10.1103/PhysRevApplied.19.014074
[4] Bipolar thermoelectric superconducting single-electron transistor S. Battisti, G. De Simoni, L. Chirolli, A.
Braggio, F. Giazotto arXiv preprint arXiv:2305.14114 https://arxiv.org/abs/2303.07173
[5] A highly sensitive broadband superconducting thermoelectric single-photon detector F. Paolucci, G.
Germanese, A. Braggio, F. Giazotto Applied Phys. Lett. 122, 173503
(2023)[Patented] https://doi.org/10.1063/5.0145544
[6] BipolarThermoelectricity in Bilayer-Graphene/Superconductor Tunnel Junctions, L. Bernazzani,G.
Marchegiani,F. Giazotto,S. Roddaro,A. Braggio Phys. Rev. Applied 19, 044017
(2023) https://doi.org/10.1103/PhysRevApplied.19.044017
[7] Bipolar thermoelectrical SQUIPT (BTSQUIPT) C. Guarcello, R. Citro, F. Giazotto, A. Braggio Applied
Phys. Lett. 123, 152601 (2023) https://doi.org/10.1063/5.0169267
[8] Microwave-Assisted Thermoelectricity in S-I-S′ Tunnel Junctions A. Hijano, F.S. Bergeret, F. Giazotto, and
A. Braggio Phys. Rev. Applied 19, 044024
(2023) https://journals.aps.org/prapplied/abstract/10.1103/PhysRevApplied.19.044024
Caption: Bipolar Thermoelectric Josephson engine