Hyperfine interaction and electron-spin decoherence in graphene and carbon nanotube quantum dots

Abstract

We analytically calculate the nuclear-spin interactions of a single electron confined to a carbon nanotube or graphene quantum dot. While the conduction-band states in graphene are p-type, the accordant states in a carbon nanotube are sp-hybridized due to curvature. This leads to an interesting interplay between isotropic and anisotropic hyperfine interactions. By using only analytical methods, we are able to show how the interaction strength depends on important physical parameters, such as curvature and isotope abundances. We show that for the investigated carbon structures, the 13C hyperfine coupling strength is less than 1 mu-eV, and that the associated electron-spin decoherence time can be expected to be several tens of microseconds or longer, depending on the abundance of spin-carrying 13C nuclei. Furthermore, we find that the hyperfine-induced Knight shift is highly anisotropic, both in graphene and in nanotubes of arbitrary chirality.

9 pages, 5 figures

References in corpus (11)

• Chaotic Dirac billiard in graphene quantum dots
• Spin qubits in graphene quantum dots
• Coupling of Spin and Orbital Motion of Electrons in Carbon Nanotubes
• Hyperfine interaction in a quantum dot: Non-Markovian electron spin dynamics
• Spin decoherence of a heavy hole coupled to nuclear spins in a quantum dot
• Electron Spin Dephasing due to Hyperfine Interactions with a Nuclear Spin Bath
• Recipes for spin-based quantum computing
• Spin-orbit interaction and anomalous spin relaxation in carbon nanotube quantum dots
• Tunable few-electron double quantum dots and Klein tunnelling in ultra-clean carbon nanotubes
• Hyperfine Interactions in Graphene and Related Carbon Nanostructures
• Nuclear Magnetism and Electronic Order in 13C Nanotubes