Thomas Schäpers

---

Qubit systems based on high quality hybrid superconducting quantum devices are often
realized by using semiconductor nanowires. In core/shell GaAs/InAs nanowires,
containing a tubular conductor in the InAs shell wrapped around an insulating GaAs core,
the strong confinement near the surface ensures good coupling to a superconductor. We
present magnetotransport measurements on zincblende phase-pure GaAs/InAs
core/shell nanowires, where the reduced disorder compared to polycrystalline nanowires
is expected to result in improved transport properties. When an axial magnetic field is
penetrating the tubular conductor, h/e-periodic Aharonov-Bohm type oscillations are
observed in the magnetoconductance [1]. In addition, phase-rigid h/2e-periodic
oscillations corresponding to Altshuler-Aronov-Spivak oscillations are observed. By
temperature-dependent measurements, we identify a quasi-ballistic transport regime
with few scattering centers in the conducting shell, which nevertheless leads to an
Altshuler-Aronov-Spivak correction. In addition, Josephson junctions comprising a
core/shell GaAs/InAs nanowire as a weak link were investigated [2,3]. Here, we observed
an oscillation of the switching current in an axial magnetic field with a period of h/2e.
Work done in collaboration with: F. Basaric, A. Pawlis, V. Brajovic, K. Moors, W. Schaarman, A.
Manolescu, R. Deacon, K. Ishibashi, P. Zellekens, R. Juluri, A. M. Sanchez, J. H. Bae, H. Lüth, D.
Grützmacher, M. D. Randle, P. Perla, M. I. Lepsa, G. Behner, E. Zimmermann, B. Bennemann, C.
Krause
[1] Farah Basaric, Vladan Brajovic, Gerrit Behner, Kristof Moors, William Schaarman, Andrei
Manolescu, Raghavendra Juluri, Ana M. Sanchez, Jin Hee Bae, Hans Lüth, Detlev
Grützmacher, Alexander Pawlis, Thomas Schäpers, Aharonov-Bohm and Altshuler-Aronov-
Spivak oscillations in the quasiballistic regime in phase-pure GaAs/InAs core/shell
nanowires, Phys. Rev. B. 112, 075301 (2025).
[2] Patrick Zellekens, Russell Deacon, Pujitha Perla, Detlev Grützmacher, Mihail Ion Lepsa,
Thomas Schäpers, Koji Ishibashi, Microwave spectroscopy of Andreev states in InAs
nanowire-based hybrid junctions using a flip-chip layout, Communications Physics 5, 267
(2022).
[3] Patrick Zellekens, Russell S. Deacon, Farah Basaric, Raghavendra Juluri, Michael D Randle,
Benjamin Bennemann, Christoph Krause, Erik Zimmermann, Ana M. Sanchez, Detlev
Grützmacher, Alexander Pawlis, Koji Ishibashi, Thomas Schäpers, Flux-periodic supercurrent
oscillations in an Aharonov-Bohm-type nanowire Josephson junction, Communications
Physics 8, 363 (2025).

---

FZJ
PH2
Contact: Alina Rupp / Matteo Cacco