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GeTe Nanowires for Applications in Quantum Technology

Jülich, 5th February 2021

Researchers at the Peter Grünberg Institute, in collaboration with the University of Southern California, Los Angeles and the East China Normal University in Shanghai, succeeded in observing quantum oscillations in supercurrent in GeTe nanowires.

GeTe is well-known as a material suitable for application in memory technology. Here, the possibility is exploited to change the crystal properties and thus the bit information by means of an electric current.  Especially for applications at low temperatures, e.g. in quantum technology, many new possibilities open up due to the unique material properties. An important prerequisite here is to produce extremely small structures in the range of a few tens of nanometers.

In this project, chemical vapor deposition was used to deposit GeTe nanowires a few micrometers long with a diameter of only a few tens of nanometers. These nanowires were then integrated into electronic components in the clean room of the Helmholtz Nano Facility in Jülich and subsequently electrically measured at extremely low temperatures.

Elektronenmikroskopische Aufnahme eines GeTe Nanodrahtes und Schema zum LadungstransportElektronenmikroskopische Aufnahme eines GeTe Nanodrahtes und Schema zum Ladungstransport
Copyright: Forschungszentrum Jülich

In samples with normal conducting contacts, regular resistance oscillations were observed when a magnetic field was applied along the nanowire. These could be explained by the formation of closed-loop quantum states along the surface of the nanowire. These measurements clearly show that it is possible to create controlled quantum states in a GeTe nanowire, an important requirement for applications in quantum devices. In further experiments, the nanowires were provided with closely spaced superconducting contacts. Here, we found that the aforementioned closed-loop quantum states lead to pronounced oscillations in the Josephson supercurrent.

Our results prove that GeTe is not only interesting for classical applications in phase change media, but also has a very high potential for future quantum devices.

GeTe Naanowire: Critical current oscillations(a) Differential resistance for various magnetic fields applied along the nanowire axis. (b) Oscillations of the critical current as a function of an axial magnetic field
Copyright: Forschungszentrum Jülich

Original publication:

“Flux periodic oscillations and phase-coherent transport in GeTe nanowire-based devices”, Jinzhong Zhang, Pok-Lam Tse, Abdur-Rehman Jalil, Jonas Kölzer, Daniel Rosenbach, Martina Luysberg, Gregory Panaitov, Hans Lüth, Zhigao Hu, Detlev Grützmacher, Jia Grace Lu, Thomas Schäpers.

Nature Communications, 12, 754 (2021),