Pauli Blockade of Tunable Two-Electron Spin and Valley States in Graphene Quantum Dots
arXiv:2106.04722 · doi:10.1103/PhysRevLett.128.067702
Abstract
Pauli blockade mechanisms -- whereby carrier transport through quantum dots is blocked due to selection rules even when energetically allowed -- are a direct manifestation of the Pauli exclusion principle, as well as a key mechanism for manipulating and reading out spin qubits. Pauli spin blockade is well established for systems such as GaAs QDs, but is to be further explored for systems with additional degrees of freedom, such as the valley quantum numbers in carbon-based materials or silicon. Here we report experiments on coupled bilayer graphene double quantum dots, in which the spin and valley states are precisely controlled, enabling the observation of the two-electron combined blockade physics. We demonstrate that the doubly occupied single dot switches between two different ground states with gate and magnetic-field tuning, allowing for the switching of selection rules: with a spin-triplet--valley-singlet ground state, valley-blockade is observed; and with the spin-singlet--valley-triplet ground state, robust spin blockade is shown.
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- Orbital hybridization in graphene-based artificial atoms
- Spin-Valley Protected Kramers Pair in Bilayer Graphene
- Counting Statistics of Single Electron Transport in Bilayer Graphene Quantum Dots
- Spin-valley locked excited states spectroscopy in a one-particle bilayer graphene quantum dot
- Pauli blockade catalogue and three- and four-particle Kondo effect in bilayer graphene quantum dots
- Extended Hubbard model describing small multi-dot arrays in bilayer graphene
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- Switching spin filling sequence in a bilayer graphene quantum dot through trigonal warping
- Tunable p-n junction barriers in few-electron bilayer graphene quantum dots
- Electric-field independent spin-orbit coupling gap in hBN-encapsulated bilayer graphene
- Dipole coupling of a bilayer graphene quantum dot to a high-impedance microwave resonator
- Three-carrier spin blockade and coupling in bilayer graphene double quantum dots
- Electrically-tunable graphene nanomechanical resonators
- Phonon-limited valley life times in single-particle bilayer graphene quantum dots
- Tuning confined states and valley g-factors by quantum dot design in bilayer graphene
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- The role of antisymmetric orbitals and electron-electron interactions on the two-particle spin and valley blockade in graphene double quantum dots
- Radio-frequency charge detection on graphene electron-hole double quantum dots