SKM 2023 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 27: Focus Session: Unconventional Transport Phenomena in Low-Dimensional Superconducting Heterostructures

TT 27.1: Hauptvortrag

Mittwoch, 29. März 2023, 09:30–10:00, HSZ 03

Superconducting diode effect in Rashba superlattice — •Teruo Ono — Kyoto University, Japan

The diode effect is fundamental to electronic devices and is widely used in rectifiers and AC-DC converters. However, conventional diodes have an energy loss due to finite resistance. We found the superconducting diode effect (SDE) in Nb/V/Ta superlattices with a polar structure, which is the ultimate diode effect exhibiting a superconducting state in one direction and a normal state in the other [1-3]. SDE can be considered as the nonreciprocity of the critical current for the metal-superconductor transition. We also found the reverse effect, i.e., the nonreciprocal critical magnetic field under the application of the supercurrent [4]. We also found that the polarity of the superconducting diode shows a sign reversal as a magnetic field is increased, which can be considered as the crossover and phase transitions of the finite-momentum pairing states predicted theoretically [5]. SDE in Nb/V/Ta superlattices needs an application of an external magnetic field to break the time reversal symmetry, which is a disadvantage in applications. We recently succeeded in demonstrating SDE in a zero-field by introducing ferromagnetic layers in superlattices [6]. The polarity of the SDE is controlled by the magnetization direction of the ferromagnetic layer, leading to development of novel non-volatile memories and logic circuits with ultralow power consumption.

[1] J. Magn. Soc. Japan 43, 17 (2019)

[2] Nature 584, 373 (2020)

[3] Jpn. J. Appl. Phys. 60, 060902 (2021)

[4] Appl. Phys. Express 14, 073003 (2021)

[5] Phys. Rev. Lett. 128, 037001 (2022)

[6] Nat. Nanotechnol. 17, 823 (2022)