Abstract
A superconducting hard gap in hybrid superconductor-semiconductor devices has been found to be necessary to access topological superconductivity that hosts Majorana modes (non-Abelian excitation). This requires the formation of homogeneous and barrier-free interfaces between the superconductor and semiconductor. Here, a new platform is reported for topological superconductivity based on hybrid Nb-In0.75 Ga0.25 As-quantum-well-Nb that results in hard superconducting gap detection in symmetric, planar, and ballistic Josephson junctions. It is shown that with careful etching, sputtered Nb films can make high-quality and transparent contacts to the In0.75 Ga0.25 As quantum well, and the differential resistance and critical current measurements of these devices are discussed as a function of temperature and magnetic field. It is demonstrated that proximity-induced superconductivity in the In0.75 Ga0.25 As-quantum-well 2D electron gas results in the detection of a hard gap in four out of seven junctions on a chip with critical current values of up to 0.2 µA and transmission probabilities of >0.96. The results, together with the large g-factor and Rashba spin-orbit coupling in In0.75 Ga0.25 As quantum wells, which indeed can be tuned by the indium composition, suggest that the Nb-In0.75 Ga0.25 As-Nb system can be an excellent candidate to achieve topological phase and to realize hybrid topological superconducting devices.
Highlights
A superconducting hard gap in hybrid superconductor–semiconductor computers.[2,3,4] there still is a fundamental technological problem devices has been found to be necessary to access topological superconducin the fabrication of highly transparent tivity that hosts Majorana modes
This work involved the in situ deposition of Al on indium arsenide (InAs) in a molecular beam epitaxy (MBE) chamber after the semiconductor growth has been completed.[5]
We study the fabrication and low-temperature measurements of eight symmetric Similar high-quality semiconducting–superconducting (S–Sm–S) planar and ballistic Josephson junctions on a chip containing an In0.75Ga0.25As quantum well in a heterostructure in which each junction consists of two identical niobium (Nb) superconducting electrodes in contact with a 2DEG that is formed ≈120 nm below the wafer’s surface
Summary
A superconducting hard gap in hybrid superconductor–semiconductor computers.[2,3,4] there still is a fundamental technological problem devices has been found to be necessary to access topological superconducin the fabrication of highly transparent tivity that hosts Majorana modes (non-Abelian excitation). Nb films can make high-quality and transparent contacts to the In0.75Ga0.25As quantum well, and the differential resistance and critical current measurements of these devices are discussed as a function of temperature and magnetic field.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have