Orbital-hybridization-induced Ising-type superconductivity in a confined gallium layer

Area of Science:

• Condensed Matter Physics
• Materials Science
• Superconductivity

Background:

• Low-dimensional superconductors exhibit unique properties due to quantum confinement and interfacial effects.
• These phenomena can alter Cooper-pair wavefunctions, leading to unconventional superconducting states.
• Interfacial hybridization plays a crucial role in tuning superconducting properties.

Purpose of the Study:

• To synthesize and investigate a gallium trilayer system for unconventional superconductivity.
• To explore the effects of quantum confinement and interfacial hybridization on superconductivity.
• To demonstrate interfacial Ising-type superconductivity driven by atomic orbital hybridization.

Main Methods:

• Plasma-free confinement epitaxy using a carbon buffer layer to create a graphene/gallium trilayer/6H-SiC heterostructure.
• Electrical transport measurements to determine superconducting properties, including the upper critical magnetic field.
• Angle-resolved photoemission spectroscopy (ARPES) and theoretical calculations to probe electronic structure and spin textures.

Main Results:

• Successful synthesis of a confined gallium trilayer exhibiting interfacial Ising-type superconductivity.
• Observation of an exceptionally high in-plane upper critical magnetic field (~21.98 T), 3.38 times the Pauli paramagnetic limit.
• ARPES and theoretical calculations confirmed split Fermi surfaces with Ising-type spin textures due to strong SiC hybridization.

Conclusions:

• The study establishes a novel strategy for achieving unconventional pairing wavefunctions.
• Synergistic effects of quantum confinement and interfacial hybridization are key to realizing these states.
• This work opens new avenues for designing advanced superconducting materials.