TY - JOUR
T1 - Parity transitions in the superconducting ground state of hybrid InSb-Al Coulomb islands
AU - Shen, Jie
AU - Heedt, Sebastian
AU - Borsoi, Francesco
AU - van Heck, Bernard
AU - Gazibegovic, Sasa
AU - Op Het Veld, Roy L.M.
AU - Car, Diana
AU - Ramakers, Senja J.J.
AU - Wang, Guanzhong
AU - Xu, Di
AU - Bouman, Daniël
AU - Geresdi, Attila
AU - Bakkers, Erik P.A.M.
AU - Kouwenhoven, Leo P.
PY - 2018
Y1 - 2018
N2 - The number of electrons in small metallic or semiconducting islands is quantised. When tunnelling is enabled via opaque barriers this number can change by an integer. In superconductors the addition is in units of two electron charges (2e), reflecting that the Cooper pair condensate must have an even parity. This ground state (GS) is foundational for all superconducting qubit devices. Here, we study a hybrid superconducting-semiconducting island and find three typical GS evolutions in a parallel magnetic field: a robust 2e-periodic even-parity GS, a transition to a 2e-periodic odd-parity GS, and a transition from a 2e- to a 1e-periodic GS. The 2e-periodic odd-parity GS persistent in gate-voltage occurs when a spin-resolved subgap state crosses zero energy. For our 1e-periodic GSs we explicitly show the origin being a single zero-energy state gapped from the continuum, i.e., compatible with an Andreev bound states stabilized at zero energy or the presence of Majorana zero modes.
AB - The number of electrons in small metallic or semiconducting islands is quantised. When tunnelling is enabled via opaque barriers this number can change by an integer. In superconductors the addition is in units of two electron charges (2e), reflecting that the Cooper pair condensate must have an even parity. This ground state (GS) is foundational for all superconducting qubit devices. Here, we study a hybrid superconducting-semiconducting island and find three typical GS evolutions in a parallel magnetic field: a robust 2e-periodic even-parity GS, a transition to a 2e-periodic odd-parity GS, and a transition from a 2e- to a 1e-periodic GS. The 2e-periodic odd-parity GS persistent in gate-voltage occurs when a spin-resolved subgap state crosses zero energy. For our 1e-periodic GSs we explicitly show the origin being a single zero-energy state gapped from the continuum, i.e., compatible with an Andreev bound states stabilized at zero energy or the presence of Majorana zero modes.
UR - http://www.scopus.com/inward/record.url?scp=85056625092&partnerID=8YFLogxK
U2 - 10.1038/s41467-018-07279-7
DO - 10.1038/s41467-018-07279-7
M3 - Article
C2 - 30442935
AN - SCOPUS:85056625092
SN - 2041-1723
VL - 9
JO - Nature Communications
JF - Nature Communications
IS - 1
ER -