Prof.  Yu-Xian  Li
Hebei Normal University,  China

Title: Andreev reflection and Josephson current in Weyl semimetals

Abstract:

Double local and double nonlocal Andreev reflections in a nodal-line semimetal-superconductor-nodal-line semimetal junction were investigated. Double Andreev reflections (the specular Andreev reflection and the retro-Andreev reflection), double normal reflections (the specular normal reflection and the retronormal reflection), double electron transmissions (the specular electron transmission and the normal electron transmission), and double crossed Andreev reflections (the specular crossed Andreev reflection and the crossed Andreev reflection) exist simultaneously when an electron incidents from the semimetal side.

The supercurrent of the superconductor (SC)–Weyl semimetal–SC Josephson junction hybrid system is studied. According to the different edge states, the Fermi arcs are divided into three regions: the symmetric, topological, and insulated regions. The supercurrent is suppressed in the symmetric region. In the topological region, the supercurrent increases with increasing θ. The supercurrent is almost zero in the insulated region due to the presence of the energy gap.

 

1. Yun-Xia Wang, Xing Wang, and Yu-Xian Li, Double local and double nonlocal Andreev reflections in nodal-line semimetal-superconducting heterostructures, PHYSICAL REVIEW B 105, 195402 (2022).

2. Xing Wang, Kai-Yi Lyu, Juntao Song, and Yu-Xian Li, Josephson current controlled by Fermi-arc surface states of Weyl semimetals， PHYSICAL REVIEW B 109, 235435 (2024).

3. Xing Wang and Yu-Xian Li, Andreev reflection imaging and longitudinal shift of pseudospin-1 fermions in two-dimensional materials, Appl. Phys. Lett. 123, 243102 (2023).

Biography: