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(Seminar) Sub-gap states and supercurrent in hybrid superconductor-nanowire based quantum dot systems
2019-04-24  【 】【打印】【关闭

CAS Key Laboratory of Theoretical Physics

Institute of Theoretical Physics

Chinese Academy of Sciences

Seminar

Title

题目

Sub-gap states and supercurrent in hybrid superconductor-nanowire based quantum dot systems

Speaker

报告人

Kasper Grove-Rasmussen

Affiliation

所在单位

Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen

Date

日期

2019年4月24日(周三)上午10:30
 

Venue

地点

五分彩APPSeminar Room 322 Old ITP Building

Abstract

摘要

I will present some of our recent understanding on quantum states in hybrid superconductor (S)-InAs semiconductor nanowire devices. When coupling a superconductor to a quantum dot (QD) system, the electron spin may be screened by quasiparticles above the gap in the superconductor similarly to the Kondo effect. This screening results in so-called Yu-Shiba-Rusinov (YSR) sub-gap states, which we explore in bottom-gated hybrid superconductor-nanowire single and double dot devices. The YSR state can qualitatively be modelled by using a simple zero-band width approximation, which is compared to measurements in single [1] and double quantum dots [2] coupled to a single superconductor, i.e. the N-QD-S and N-double QD-S configurations, respectively, where N is a normal electrode. Interestingly, in the latter case, the characteristic double dot honeycomb stability diagram is shown to be qualitatively different in the superconducting state for some coupling regimes. Finally, I will present, how supercurrent through these double dot structures in the S-double QD-S geometry can be used to identify the YSR ground state via a 0 to p transition in the current phase relation [3,4]. [1] A. Jellinggaard et al., Phys. Rev. B 94, 064520 (2016). [2] K. Grove-Rasmussen et al., Nat. Comm. 9 : 2376 (2018). [3] J.C. Estrada Saldana et al., Phys. Rev. Lett. 121, 257701 (2018) [4] J.C. Estrada Saldana et al., arXiv:1812.09303.

Contact Person

所内联系人

Panagiotis Kotetes
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