Spin current generation and magnetic response in carbon nanotubes by the twisting phonon mode

Abstract

We theoretically investigate spin current and magnetic response induced by the twisting phonon mode in carbon nanotubes via the spin-rotation coupling. An effective magnetic field due to the twisting mode induces both spin and orbital magnetizations. The induced spin and orbital magnetizations have both radial and axial components. We show that AC pure spin current is generated by the twisting phonon mode. The magnitude of the spin current and orbital magnetization for a (10,10) armchair nanotube is estimated as an example. We find that the AC pure spin current is detectable in magnitude when the frequency of the twisting mode is of the order of GHz, and that the orbital magnetization is found to be larger than the spin magnetization.PACS numbers: 61.48. De, Introduction. Carbon nanotubes (CNTs) have been studied extensively, and today various interesting physical characters of CNTs have been reported. CNTs can be regarded as rolls of graphene sheets, and therefore their electronic bands are closely related with those of graphene. In graphene, the electronic bands form linear dispersion called a Dirac cone. By rolling the graphene into a CNT, the band structure becomes a metal or semiconductor depending on its chirality. From the viewpoint of spin transport, the spin-orbit interaction of CNT is so weak that spin current cannot be generated for CNT alone by usual methods which require strong spin-orbit interaction.

Theory of spin hydrodynamic generation

“…Recently, an alternative scheme has been proposed, wherein spin-rotation coupling 8 is exploited for generating spin currents [9][10][11] . The spin-rotation coupling refers to the fundamental coupling between spin and mechanical rotational motion and emerges in both ferromagnetic 12 and paramagnetic 13,14 metals as well as in nuclear spin systems 15,16 .…”

Spin Connections for Nonrelativistic Electrons on Curves and Surfaces

“…Spintronics using circuits is technologically important application [83][84][85][86][87] . Spin connections arising from phonon excitations and lattice deformation 88,89 are essential ingredients to fully understand mechanical effects on electrons in solids, where the backreaction on lattice will also have intriguing effects 90 . It is of interdisciplinary interest to study biochemical objects such as DNA helices from physics viewpoints [91][92][93] .…”

Ab initio materials physics and microscopic electrodynamics of media

“…In fact, the spin magnetization is actually not outside the scope of the Kubo formalism. Instead, it can be included by a spin contribution to the electric current (which is distinct from the current of spin considered in recent applications [147][148][149][150][151][152][153][154][155][156][157]). This spin contribution to the electric current is of the following form (see e.g.…”