Large second-order Josephson effect in planar superconductor-semiconductor junctions

Zhang, Po; Zarassi, Azarin; Jarjat, Lucas; Van de Sande, Vince; Pendharkar, Mihir; Lee, J. S.; Dempsey, Connor P.; McFadden, Anthony; Harrington, Sean David; Dong, Jason T.; Wu, H.; Chen, A. -H.; Hocevar, Moïra; Palmstrøm, C. J.; Frolov, Sergey M.

doi:10.21468/SciPostPhys.16.1.030

SciPost Physics

Large second-order Josephson effect in planar superconductor-semiconductor junctions

P. Zhang, A. Zarassi, L. Jarjat, V. Van de Sande, M. Pendharkar, J. S. Lee, C. P. Dempsey, A. P. McFadden, S. D. Harrington, J. T. Dong, H. Wu, A. -H. Chen, M. Hocevar, C. J. Palmstrøm, S. M. Frolov

SciPost Phys. 16, 030 (2024) · published 25 January 2024

doi: 10.21468/SciPostPhys.16.1.030
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Abstract

We investigate the current-phase relations of Al/InAs-quantum well planar Josephson junctions fabricated using nanowire shadowing technique. Based on several experiments, we conclude that the junctions exhibit an unusually large second-order Josephson harmonic, the $\sin(2\varphi)$ term. First, superconducting quantum interference devices (dc-SQUIDs) show half-periodic oscillations, tunable by gate voltages as well as magnetic flux. Second, Josephson junction devices exhibit kinks near half-flux quantum in supercurrent diffraction patterns. Third, half-integer Shapiro steps are present in the junctions. Similar phenomena are observed in Sn/InAs quantum well devices. We perform data fitting to a numerical model with a two-component current phase relation. Analysis including a loop inductance suggests that the sign of the second harmonic term is negative. The microscopic origins of the observed effect remain to be understood. We consider alternative explanations which can account for some but not all of the evidence.

TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.16.1.030
TI  - Large second-order Josephson effect in planar superconductor-semiconductor junctions
PY  - 2024/01/25
UR  - https://scipost.org/SciPostPhys.16.1.030
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 16
IS  - 1
SP  - 030
A1  - Zhang, Po
AU  - Zarassi, Azarin
AU  - Jarjat, Lucas
AU  - Van de Sande, Vince
AU  - Pendharkar, Mihir
AU  - Lee, J. S.
AU  - Dempsey, Connor P.
AU  - McFadden, Anthony
AU  - Harrington, Sean David
AU  - Dong, Jason T.
AU  - Wu, H.
AU  - Chen, A. -H.
AU  - Hocevar, Moïra
AU  - Palmstrøm, C. J.
AU  - Frolov, Sergey M.
AB  - We investigate the current-phase relations of Al/InAs-quantum well planar Josephson junctions fabricated using nanowire shadowing technique. Based on several experiments, we conclude that the junctions exhibit an unusually large second-order Josephson harmonic, the $\sin(2\varphi)$ term. First, superconducting quantum interference devices (dc-SQUIDs) show half-periodic oscillations, tunable by gate voltages as well as magnetic flux. Second, Josephson junction devices exhibit kinks near half-flux quantum in supercurrent diffraction patterns. Third, half-integer Shapiro steps are present in the junctions. Similar phenomena are observed in Sn/InAs quantum well devices. We perform data fitting to a numerical model with a two-component current phase relation. Analysis including a loop inductance suggests that the sign of the second harmonic term is negative. The microscopic origins of the observed effect remain to be understood. We consider alternative explanations which can account for some but not all of the evidence.
ER  -

@Article{10.21468/SciPostPhys.16.1.030,
	title={{Large second-order Josephson effect in planar superconductor-semiconductor junctions}},
	author={P. Zhang and A. Zarassi and L. Jarjat and V. Van de Sande and M. Pendharkar and J. S. Lee and C. P. Dempsey and A. P. McFadden and S. D. Harrington and J. T. Dong and H. Wu and A. -H. Chen and M. Hocevar and C. J. Palmstrøm and S. M. Frolov},
	journal={SciPost Phys.},
	volume={16},
	pages={030},
	year={2024},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.16.1.030},
	url={https://scipost.org/10.21468/SciPostPhys.16.1.030},
}

Cited by 6

Authors / Affiliations: mappings to Contributors and Organizations

See all Organizations.

¹ Po Zhang,
¹ Azarin Zarassi,
² Lucas Jarjat,
³ Vince Van de Sande,
⁴ Mihir Pendharkar,
⁴ J. S. Lee,
⁴ Connor P. Dempsey,
⁴ Anthony McFadden,
⁴ Sean David Harrington,
⁴ Jason T. Dong,
¹ H. Wu,
⁵ A. -H. Chen,
⁵ Moïra Hocevar,
⁴ C. J. Palmstrøm,
¹ Sergey M. Frolov

Funders for the research work leading to this publication

Agence Nationale de la Recherche [ANR]
Army Research Office (ARO) (through Organization: United States Army Research Laboratory [ARL])
National Science Foundation [NSF]
Office of Naval Research [ONR]