Tunnel current control of relaxation of a nuclear spin placed on a nanomechanical oscillator

Abstract

We propose a mechanism to decrease the time needed to establish nuclear spin polarization by resonant coupling of the nuclear spins to a heat bath composed of nanomechanical degrees of freedom. To achieve this, we suggest that the nuclear spins be attached to the tip of a cantilever oscillating in a nonuniform magnetic field in the presence of another, perpendicular, constant, uniform magnetic field. The gradient of the magnetic field couples the spin and mechanical degrees of freedom, inducing an additional spin relaxation mechanism. The nanomechanical oscillator can also serve as one of the contacts of a tunnel junction, facilitating a voltage control of the nuclear spin relaxation time.