Direct microwave spectroscopy of Andreev bound states in planar Ge Josephson junctions

Fuente: arXiv
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Main Authors: Hinderling, M., Kate, S. C. ten, Coraiola, M., Haxell, D. Z., Stiefel, M., Mergenthaler, M., Paredes, S., Bedell, S. W., Sabonis, D., Nichele, F.
Format: Preprint
Published: 2024
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author Hinderling, M.
Kate, S. C. ten
Coraiola, M.
Haxell, D. Z.
Stiefel, M.
Mergenthaler, M.
Paredes, S.
Bedell, S. W.
Sabonis, D.
Nichele, F.
author_facet Hinderling, M.
Kate, S. C. ten
Coraiola, M.
Haxell, D. Z.
Stiefel, M.
Mergenthaler, M.
Paredes, S.
Bedell, S. W.
Sabonis, D.
Nichele, F.
contents We demonstrate microwave measurements of the Andreev bound state (ABS) spectrum in planar Josephson junctions (JJs) defined in Ge high mobility two-dimensional hole gases contacted by superconducting PtSiGe. The JJs and readout circuitry are located on separate chips and inductively coupled via flip-chip bonding. For a device with $350~\mathrm{nm}$ junction length, spectroscopic signatures were consistent with the short-junction limit, with an induced superconducting gap $Δ^{*}\approx48~\mathrm{μeV}$ and transmission $τ\approx 0.94$. The interaction between the highest-transmission ABS and the resonator was well described by a Jaynes-Cummings model with a vacuum Rabi splitting of approximately $6~\mathrm{MHz}$. A device with junction length of $1~μm$ showed an ABS spectrum consistent with a long junction model. Time-resolved monitoring of the readout resonator in the dispersive regime revealed gate-voltage tunable junction parity fluctuations on the timescale of seconds. Our work indicates a viable path towards hybrid quantum devices based on planar Ge.
format Preprint
id arxiv_https___arxiv_org_abs_2403_03800
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Direct microwave spectroscopy of Andreev bound states in planar Ge Josephson junctions
Hinderling, M.
Kate, S. C. ten
Coraiola, M.
Haxell, D. Z.
Stiefel, M.
Mergenthaler, M.
Paredes, S.
Bedell, S. W.
Sabonis, D.
Nichele, F.
Mesoscale and Nanoscale Physics
Superconductivity
We demonstrate microwave measurements of the Andreev bound state (ABS) spectrum in planar Josephson junctions (JJs) defined in Ge high mobility two-dimensional hole gases contacted by superconducting PtSiGe. The JJs and readout circuitry are located on separate chips and inductively coupled via flip-chip bonding. For a device with $350~\mathrm{nm}$ junction length, spectroscopic signatures were consistent with the short-junction limit, with an induced superconducting gap $Δ^{*}\approx48~\mathrm{μeV}$ and transmission $τ\approx 0.94$. The interaction between the highest-transmission ABS and the resonator was well described by a Jaynes-Cummings model with a vacuum Rabi splitting of approximately $6~\mathrm{MHz}$. A device with junction length of $1~μm$ showed an ABS spectrum consistent with a long junction model. Time-resolved monitoring of the readout resonator in the dispersive regime revealed gate-voltage tunable junction parity fluctuations on the timescale of seconds. Our work indicates a viable path towards hybrid quantum devices based on planar Ge.
title Direct microwave spectroscopy of Andreev bound states in planar Ge Josephson junctions
topic Mesoscale and Nanoscale Physics
Superconductivity
url https://arxiv.org/abs/2403.03800