Berlin 2024 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 35: Superconducting Electronics: SQUIDs, Circuit QED
TT 35.6: Vortrag
Mittwoch, 20. März 2024, 10:45–11:00, H 2053
Microwave measurements of a Josephson junction based on a 2D HgTe quantum well — •Wei Liu1,2, Stanislau Piatrusha1,2, Lena Fürst1,2, Lukas Lunzer1,2, Martin P. Stehno1,2, and Laurens W. Molenkamp1,2 — 1Experimentelle Physik III, Physikalisches Institut, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany. — 2Institute for Topological Insulators, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
We measured the microwave response of a rf SQUID based on a 2D HgTe Josephson junction, by inductively coupling it to a superconducting resonator. We extract both the current-phase relation and the phase dependent dynamic dissipation between the Andreev bound states. We focus on non-topological ABSs and study their response to temperature, magnetic field and strong microwave drive. The dynamic dissipation shows a temperature-driven crossover from 2π-periodic oscillations to a π-quasiperiodic pattern with different peak heights at even and odd values of phase π. We show how the magnetic field modulates the current phase relation and the dynamic dissipation peak, leading to effects such as the half flux periodicity, the Josephson diode effect and the splitting and combining of the dissipative peaks. Under a strong microwave irradiation, both the supercurrent and the dynamic dissipation deviate from the adiabatic Josephson effect. We attribute this to the nonequilibrium occupation of Andreev bound states due to photon induced transitions across the energy gap, which enables us to map out the phase dependent effective Andreev gap.
Keywords: Josepphson junction; rf SQUID; nonequilibrium dynamics