Electron Spin Relaxation in Graphene Nanoribbon Quantum Dots

Abstract

Graphene is promising as a host material for electron spin qubits because of its predicted potential for long coherence times. In armchair graphene nanoribbons (aGNRs) a small bandgap is opened, allowing for electrically gated quantum dots, and furthermore the valley degeneracy is lifted. The spin lifetime T_1 is limited by spin relaxation, where the Zeeman energy is absorbed by lattice vibrations, mediated by spin-orbit and electron-phonon coupling. We have calculated T_1 by treating all couplings analytically and find that T_1 can be in the range of seconds for several reasons: (i) low phonon density of states away from Van Hove singularities; (ii) destructive interference between two relaxation mechanisms; (iii) Van Vleck cancellation at low magnetic fields; (iv) vanishing coupling to out-of-plane modes in lowest order due to the electronic structure of aGNRs. Owing to the vanishing nuclear spin of 12C, T_1 may be a good measure for overall coherence. These results and recent advances in the controlled production of graphene nanoribbons make this system interesting for spintronics applications.

11 pages, 9 figures, v2: published version

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Cited by in corpus (12)

• Graphene nanoribbons for quantum electronics
• Electrostatically confined monolayer graphene quantum dots with orbital and valley splittings
• Spin relaxation in a single-electron graphene quantum dot
• Ab initio spin-flip conductance of hydrogenated graphene nanoribbons: Spin-orbit interaction and scattering with local impurity spins
• Graphene Enabled Low-Control Quantum Gates between Static and Mobile Spins
• Spintronics with graphene quantum dots
• Ultra long spin decoherence times in graphene quantum dots with a small number of nuclear spins
• Ab initio modelling of spin relaxation lengths in disordered graphene nanoribbons†
• Electronic structure of fullerene nanoribbons
• The role of the Rashba coupling in spin current of monolayer gapped graphene
• Edge channel confinement in a bilayer graphene $n$-$p$-$n$ quantum dot
• Acoustic phonons, spin-phonon coupling and spin relaxation via the lattice reorientation mechanism in hexagonal germanium nanowires