TY - JOUR
T1 - Highly Transparent Gatable Superconducting Shadow Junctions
AU - Khan, Sabbir A.
AU - Lampadaris, Charalampos
AU - Cui, Ajuan
AU - Stampfer, Lukas
AU - Liu, Yu
AU - Pauka, Sebastian J.
AU - Cachaza, Martin E.
AU - Fiordaliso, Elisabetta M.
AU - Korneychuk, Svetlana
PY - 2020/11/24
Y1 - 2020/11/24
N2 - Gate-tunable junctions are key elements in quantum devices based on hybrid semiconductor-superconductor materials. They serve multiple purposes ranging from tunnel spectroscopy probes to voltage-controlled qubit operations in gatemon and topological qubits. Common to all is that junction transparency plays a critical role. In this study, we grow single-crystalline InAs, InSb, and InAs1-xSbx semiconductor nanowires with epitaxial Al, Sn, and Pb superconductors and in situ shadowed junctions in a single-step molecular beam epitaxy process. We investigate correlations between fabrication parameters, junction morphologies, and electronic transport properties of the junctions and show that the examined in situ shadowed junctions are of significantly higher quality than the etched junctions. By varying the edge sharpness of the shadow junctions, we show that the sharpest edges yield the highest junction transparency for all three examined semiconductors. Further, critical supercurrent measurements reveal an extraordinarily high ICRN, close to the KO-2 limit. This study demonstrates a promising engineering path toward reliable gate-tunable superconducting qubits.
AB - Gate-tunable junctions are key elements in quantum devices based on hybrid semiconductor-superconductor materials. They serve multiple purposes ranging from tunnel spectroscopy probes to voltage-controlled qubit operations in gatemon and topological qubits. Common to all is that junction transparency plays a critical role. In this study, we grow single-crystalline InAs, InSb, and InAs1-xSbx semiconductor nanowires with epitaxial Al, Sn, and Pb superconductors and in situ shadowed junctions in a single-step molecular beam epitaxy process. We investigate correlations between fabrication parameters, junction morphologies, and electronic transport properties of the junctions and show that the examined in situ shadowed junctions are of significantly higher quality than the etched junctions. By varying the edge sharpness of the shadow junctions, we show that the sharpest edges yield the highest junction transparency for all three examined semiconductors. Further, critical supercurrent measurements reveal an extraordinarily high ICRN, close to the KO-2 limit. This study demonstrates a promising engineering path toward reliable gate-tunable superconducting qubits.
KW - ballistic transport
KW - Majorana bound states
KW - quantum computing
KW - semiconductor−superconductor nanowires
KW - shadow junctions
KW - topological materials
UR - http://www.scopus.com/inward/record.url?scp=85096883934&partnerID=8YFLogxK
U2 - 10.1021/acsnano.0c02979
DO - 10.1021/acsnano.0c02979
M3 - Article
C2 - 32396328
AN - SCOPUS:85096883934
SN - 1936-086X
VL - 14
SP - 14605
EP - 14615
JO - ACS Nano
JF - ACS Nano
IS - 11
ER -