Recently, Associate Professor He Mian Yi, a tenured track faculty member at the Tsung-Dao Lee Institute and the School of Physics and Astronomy at Shanghai Jiao Tong University, collaborated with Professor Chao-Xing Liu and Professor Cui-Zu Chang's teams from the Department of Physics at Pennsylvania State University in the United States to publish a research paper titled 'Orbital-hybridization-induced Ising-type superconductivity in a confined Gallium layer' in Nature Materials. This study breaks through traditional understanding by discovering, for the first time, an Ising-type superconducting state induced by orbital hybridization in thin films of the light element gallium (Ga). The research team innovatively employed a confined epitaxial technique without plasma intervention, assisted solely by a carbon buffer layer, to successfully fabricate a sandwich-structured heterojunction that remains stable under atmospheric conditions: a gallium thin film, merely three atoms thick, is confined between a double-layer graphene capping layer and a silicon carbide substrate. In this quantum-confined environment, the electronic structure and spin properties of the gallium thin film undergo fundamental changes, exhibiting an in-plane upper critical magnetic field of up to 21.98 tesla, far exceeding the theoretical limit for conventional superconductors and reaching 3.38 times the Pauli paramagnetic limit. The study reveals a strong orbital hybridization effect between the underlying gallium atoms and the silicon atoms of the silicon carbide substrate, which reshapes the wave function of Cooper pairs in the gallium layer, inducing a 'spin-valley locking' effect that endows the Cooper pairs with the ability to resist strong in-plane magnetic fields. This discovery not only eliminates the reliance on specific heavy-element materials but also opens up new avenues for the integration of superconducting devices based on large-size wafers and low-power spintronic technologies.
