Spin-dependent inertial force and spin current in accelerating systems

Abstract

The spin-dependent inertial force in an accelerating system under the presence of electromagnetic fields is derived from the generally covariant Dirac equation. Spin currents are evaluated by the force up to the lowest order of the spin-orbit coupling in both ballistic and diffusive regimes. We give an interpretation of the inertial effect of linear acceleration on an electron as an effective electric field and show that mechanical vibration in a high frequency resonator can create a spin current via the spin-orbit interaction augmented by the linear acceleration.Comment: 11 pages,4 figure

On an atom with a magnetic quadrupole moment in a rotating frame

“…Rotating effects have also been observed in the quantum Hall effect [16], spintronics [17][18][19], quantum rings [20][21][22], Bose-Einstein condensation [23] and in the presence of the Kratzer potential [24].…”

Excitation of Ferromagnetic Resonance Using Surface Acoustic Waves

“…On the other hand, zero-standbypower solid-state memory devices using nonvolatile magnetization in ferromagnetic materials and rewritable logic devices were recently proposed, and low-power fast control is required for magnetization of nanodots embedded in integration circuits. Matsuo and colleagues showed theoretically that when rotational motion is applied to crystal lattice of nonmagnetic metals, effective magnetic field is generated in the rotation direction of velocity field of lattice points (Barnett effect), and in this orientation, spin separation occurs just as in Stern-Gerlach experiment, that is, spin current can be generated (SRC: Spin Rotation Coupling) [14]. Hence, much attention is attracted by magnetization control using spin currents that can directly apply torque to magnetization by means of exchange interaction, without generating Ampere's magnetic field.…”

“…This approach is based on exchange between mechanical rotation and electron's angular momentum that was long known as Einstein-de Haas effect [12] and its reciprocal effect (Barnett effect) [13]. Matsuo and colleagues showed theoretically that when rotational motion is applied to crystal lattice of nonmagnetic metals, effective magnetic field is generated in the rotation direction of velocity field of lattice points (Barnett effect), and in this orientation, spin separation occurs just as in Stern-Gerlach experiment, that is, spin current can be generated (SRC: Spin Rotation Coupling) [14]. In this theory, generated spin current is proportional to metal's electric conductivity and spin relaxation time; therefore, metals with weak spin-orbit interaction such as Cu and Al are usable as spin current sources [15].…”

Mechanical generation of spin current

“…Such an asymmetry originates from the space-time asymmetry of a general coordinate transformation [41,42].…”

“…The electron sector of the Hamiltonian is written as (20) where B = m /e is known as the Barnett field, which is the effective magnetic field due to mechanical rotation and the quantum mechanical origin of the Barnett effect. The expansion of the order of 1/m 2 yields the spin-orbit coupling and the Darwin terms augmented by inertial effects [39][40][41]:…”