Individually addressable double quantum dots formed with nanowire polytypes and identified by epitaxial markers

TY - JOUR

T1 - Individually addressable double quantum dots formed with nanowire polytypes and identified by epitaxial markers

AU - Barker, D.

AU - Lehmann, S.

AU - Namazi, L.

AU - Nilsson, M.

AU - Thelander, C.

AU - Dick, K. A.

AU - Maisi, V. F.

PY - 2019

Y1 - 2019

N2 - Double quantum dots (DQDs) hold great promise as building blocks for quantum technology as they allow for two electronic states to coherently couple. Defining QDs with materials rather than using electrostatic gating allows for QDs with a hard-wall confinement potential and more robust charge and spin states. An unresolved problem is how to individually address these QDs, which is necessary for controlling quantum states. We here report the fabrication of DQD devices defined by the conduction band edge offset at the interface of the wurtzite and zinc blende crystal phases of InAs in nanowires. By using sacrificial epitaxial GaSb markers selectively forming on one crystal phase, we are able to precisely align gate electrodes allowing us to probe and control each QD independently. We hence observe textbooklike charge stability diagrams, a discrete energy spectrum, and electron numbers consistent with theoretical estimates and investigate the tunability of the devices, finding that changing the electron number can be used to tune the tunnel barrier as expected by simple band diagram arguments.

AB - Double quantum dots (DQDs) hold great promise as building blocks for quantum technology as they allow for two electronic states to coherently couple. Defining QDs with materials rather than using electrostatic gating allows for QDs with a hard-wall confinement potential and more robust charge and spin states. An unresolved problem is how to individually address these QDs, which is necessary for controlling quantum states. We here report the fabrication of DQD devices defined by the conduction band edge offset at the interface of the wurtzite and zinc blende crystal phases of InAs in nanowires. By using sacrificial epitaxial GaSb markers selectively forming on one crystal phase, we are able to precisely align gate electrodes allowing us to probe and control each QD independently. We hence observe textbooklike charge stability diagrams, a discrete energy spectrum, and electron numbers consistent with theoretical estimates and investigate the tunability of the devices, finding that changing the electron number can be used to tune the tunnel barrier as expected by simple band diagram arguments.

U2 - 10.1063/1.5089275

DO - 10.1063/1.5089275

M3 - Article

VL - 114

JO - Applied Physics Letters

T2 - Applied Physics Letters

JF - Applied Physics Letters

SN - 0003-6951

IS - 18

M1 - 183502

ER -