title: Pauli spin blockade in a highly tunable silicon double quantum dot.
abstract: Double quantum dots are convenient solid-state platforms to encode quantum information. Two-electron spin states can be detected and manipulated using quantum selection rules based on the Pauli exclusion principle, leading to Pauli spin blockade of electron transport for triplet states. Coherent spin states would be optimally preserved in an environment free of nuclear spins, which is achievable in silicon by isotopic purification. Here we report on a deliberately engineered, gate-defined silicon metal-oxide-semiconductor double quantum dot system. The electron occupancy of each dot and the inter-dot tunnel coupling are independently tunable by electrostatic gates. At weak inter-dot coupling we clearly observe Pauli spin blockade and measure a large intra-dot singlet-triplet splitting > 1 meV. The leakage current in spin blockade has a peculiar magnetic field dependence, unrelated to electron-nuclear effects and consistent with the effect of spin-flip cotunneling processes. The results obtained here provide excellent prospects for realising singlet-triplet qubits.
authors.affiliation: ARC Centre of Excellence for Quantum Computation and Communication Technology, School of Electrical Engineering & Telecommunications, The University of New South Wales, Sydney 2052, Australia. ns.lai@student.unsw.edu.au
authors.forename: N S
authors.initials: NS
authors.lastname: Lai
authors.forename: W H
authors.initials: WH
authors.lastname: Lim
authors.forename: C H
authors.initials: CH
authors.lastname: Yang
authors.forename: F A
authors.initials: FA
authors.lastname: Zwanenburg
authors.forename: W A
authors.initials: WA
authors.lastname: Coish
authors.forename: F
authors.initials: F
authors.lastname: Qassemi
authors.forename: A
authors.initials: A
authors.lastname: Morello
authors.forename: A S
authors.initials: AS
authors.lastname: Dzurak
mesh_terms: D025802:Electric Capacitance; D004579:Electron Transport; D004867:Equipment Design; D008855:Microscopy, Electron, Scanning; D036103:Nanotechnology; D045663:Quantum Dots; D011789:Quantum Theory; D012666:Semiconductors; D012825:Silicon
chemical_list: D012825:Silicon