Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session AAA07: V: Superconductivity IV |
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Sponsoring Units: DCMP Chair: Anushika Athauda, University of Rochester Room: Virtual Room 7 |
Wednesday, March 22, 2023 12:30PM - 12:42PM |
AAA07.00001: Non-linear non-local transport in current-bias two-dimensional vortex liquid Aleix Bou Comas, Vadim Oganesyan, Sarang Gopalakrishnan, Dror Orgad This work revisits the vortex liquid regime associated with two dimensional superconductivity and explores unusual non-equilibrium steady states, characterized by spatial modulation that should be accessible using recently developed capabilities for non-local transport. |
Wednesday, March 22, 2023 12:42PM - 12:54PM |
AAA07.00002: Pair-density-wave and chiral superconductivity in twisted bilayer transition-metal-dichalcogenides Zhengzhi Wu, Yi-Ming Wu, Hong Yao We theoretically explore possible orders induced by weak repulsive interactions in twisted bilayer transition-metal-dichalcogenides (e.g. WSe2) in the presence of an out-of-plane electric field. Using renormalization group analysis, we show that superconductivity survives even with the conventional van Hove singularities. We find topological chiral superconducting states with Chern number N=1,2,4 (namely p+ip, d+id, g+ig) appear over a large parameter region with mr filling factor around n=1. At some special values of applied electric field and in the presence of a weak out-of-plane Zeeman field, spin-polarized pair density wave (PDW) superconductivity can emerge. This spin-polarized PDW state can be probed by experiments such as spin-polarized STM measuring spin-resolved pairing gap and quasi-particle interference. Moreover, the spin-polarized PDW could lead to spin-polarized superconducting diode effect. |
Wednesday, March 22, 2023 12:54PM - 1:06PM |
AAA07.00003: Crossover between electron-electron and electron-phonon mediated pairing on the Kagome lattice Xianxin Wu, Debmalya Chakraborty, Andreas P Schnyder, Andrés Greco We study electron-electron and electron-phonon mediated pairing in the Holstein extended Hub- bard model on the Kagome lattice at the van Hove fillings, and investigate the competition and cooperation between the two pairing mechanisms. We find that electron-phonon and electron- electron pairing are cooperative in a crossover region, where the two pairing mechanisms are of comparable strength and where the filling is close to a van Hove singularity. In particular, at the p-type van Hove filling the two pairing mechanisms are cooperative in the E1u (p-wave) and B2u (fy3−3yx2-wave) channels, whereas at the m-type van Hove filling they are cooperative in the E1u channel, but weakly competitive in the B2u channel. Moreover, we show that the electron-phonon interaction acquires a significant momentum dependence, due to the sublattice texture of the Fermi surfaces, which can promote non s-wave pairing. We present a detailed analysis of these pairing propensities and discuss implications for the vanadium-based kagome superconductors AV3Sb5. |
Wednesday, March 22, 2023 1:06PM - 1:18PM |
AAA07.00004: Superconductivity in moireless multilayer graphene systems Oladunjoye A Awoga In this study, using tight-binding mean-field, group theory, and density functional theory calculations we study in detail many-body instabilities, including charge, magnetic, and superconducting orders, from electron-electron interactions in multilayer graphene systems. We find that multilayer graphene systems have possibility of hosting unconventional superconductivity as well as magnetic orders. |
Wednesday, March 22, 2023 1:18PM - 1:30PM |
AAA07.00005: Tunable superconductivity in planar Germanium Marco Valentini, Oliver Sagi, Kushagra Aggarwal, Thijs de Gijsel, Jason Jung, Marcel Verheijen, Stefano Calcaterra, Andrea Ballabio, Daniel Chrastina, Erik P. A. M. Bakkers, Giovanni Isella, Georgios Katsaros III-V materials, like InAs and InSb, are the leading platforms for the realization of gatemons and for the quest of Majorana zero modes. Here we investigate Ge as an alternative platform [1]. In the past years, dramatic progress has been made in inducing superconductivity in planar germanium either by enhancing the proximity effect using a double layer of superconductors [2] or by creating a low-disorder interface between the germanium hole gas and an annealed germanosilicide superconductor [3]. Here, we show that we can reliably induce superconductivity in a germanium hole gas by evaporating aluminum on top of a thin Si0.3Ge0.7 spacer which separates the superconductor from the quantum well. We estimate transparencies close to unity and we reveal a superconducting hard gap which can be tuned by the Si0.3Ge0.7 spacer. Finally, we show the exchange of pairs of Cooper pairs between two superconducting leads, highlighting the potential of Germanium quantum well as protected qubit [4]. |
Wednesday, March 22, 2023 1:30PM - 1:42PM |
AAA07.00006: Mixed-Pairing Superconductivity in Twisted Bilayer Transition-Metal-Dichalcogenides Mehdi Biderang Mehdi Biderang1, Mohammad-Hossein Zare2, and Thomas Scaffidi1,3 |
Wednesday, March 22, 2023 1:42PM - 1:54PM |
AAA07.00007: Dynamic screening-driven superconductivity in a two-dimensional electron gas Pengcheng Hou, Xiansheng Cai, Tao Wang, Youjin Deng, Nikolay Prokof'ev, Boris Svistunov, Kun Chen We establish the ultra-low temperature phase diagram of a two-dimensional (2D) electron gas in the dense limit where the random phase approximation (RPA) is controlled. Such a 2D Fermi gas at the RPA level cannot be a Kohn-Luttinger superconductor due to the absence of emergent attractive interaction from the back-scattering channel. Nevertheless, we develop a Cooper-pair linear response approach and identify a series of exotic superconductivity with the ultra-low superconducting temperature of 10-200~10-10 times Fermi temperature. Our results show that dynamic screening-driven superconductivity exists in the 2D electron gas, where the long-range character of Coulomb interaction is essential, and indicate a broad reconsideration of the widely used static approximation in the context of 2D superconductivity from repulsive interactions. |
Wednesday, March 22, 2023 1:54PM - 2:06PM |
AAA07.00008: Title: Probing the topological character of superconductors via nonlocal Hanbury Brown and Twiss correlations TUSARADRI MOHAPATRA
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Wednesday, March 22, 2023 2:06PM - 2:18PM |
AAA07.00009: Non-Hermitian dimerized interacting Kitaev chain: Exact and numerical solutions Sharareh Sayyad, Jose Lado Non-Hermitian models have risen as a new paradigm to manipulate and interpret various emergent quantum phenomena. While numerous studies have been focused on exploring (effective) non-Hermitian non-interacting models. The role of interactions in modifying the non-interacting non-Hermitian physics still needs to be well-explored. In this talk, I will present how incorporating many-body interactions can enrich the non-interacting physics. To be more precise, combining our exact analytical results and numerical calculations, I will discuss the phase diagram of the non-Hermitian dimerized interacting Kitaev chain. Here, the non-Hermiticty is due to the complex-valued nearest-neighbor density-density interaction strength. I will show that the ground state degeneracy of this system may be fourfold, twofold, or nondegenerate depending on the parameter regimes. I will further discuss how these degeneracies are lifted in the presence of non-Hermiticity. Elaborating on this behavior clarifies the role of non-Hermiticity in washing out multiple phases in the phase diagram of the Hermitian interacting model. |
Wednesday, March 22, 2023 2:18PM - 2:30PM |
AAA07.00010: Electron Entanglement in Composite BSCCO nanowires Linda E E Reichl Composite super/normal conducting structures provide a source of entangled electrons that result from the formation of electron-hole quasibound states in the composite structures. One signature of the electron entanglement is the existence of positive cross-correlated shot noise in the electron currents that are emitted from the nanowires. Positive shot noise is an indicator that Bell’s inequality has been violated and that electrons in the emitted electron current are entangled. We have shown that a (NS)^nN nanowire, with ballistic normal (N) segments and BSCCO superconducting (S) segments, can provide a significant source of entangled electrons. The existence of entangled electrons can also be seen in the structure of bi-partite reduced density matrix for the composite structure. Changes in the bi-partite reduced density matrix track the behavior of the shot noise and gives additional information about parameter regimes that give rise to entangled electrons.
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