Probing Spin Accumulation induced Magnetocapacitance in a Single Electron Transistor
Teik-Hui Lee1,2,3*, Chii-Dong Chen3
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Taiwan International Graduate Program, Academia Sinica, Taipei, Taiwan
3Institute of Physics, Academia Sinica, Taipei, Taiwan
* presenting author:Teik-Hui Lee,
The interplay between spin and charge in solids is currently among the most discussed topics in condensed matter physics. Such interplay gives rise to magneto-electric coupling, which in the case of solids was named magneto-electric effect, as predicted by Curie on the basis of symmetry considerations. This effect enables the manipulation of magnetization using electrical field or, conversely, the manipulation of electrical polarization by magnetic field. The latter is known as the magnetocapacitance effect. Here, we unravel the new mechanism as to how this effect is induced by spin accumulation through the formation of a tiny charge dipole. The dipole is a direct result of asymmetry in the diffusion lengths for spin-up and spin-down electrons. The proposed mechanism is realized in a ferromagnetic junction coated with a non-magnetic layer and a magnetocapacitance value as high as 40%, as determined from Coulomb-blockade diamonds, is achieved.

Keywords: Magnetocapacitance, Spin accumulation, Single electron transistor, Coulomb blockade