Quantum kinetic theory of spin-transfer torque and magnon-assisted transport in nanostructures

Abstract

We theoretically investigate the role of spin fluctuations in charge transport through a magnetic junction. Motivated by recent experiments that measure a nonlinear dependence of the current on electrical bias, we develop a systematic understanding of the interplay of charge and spin dynamics in nanoscale magnetic junctions. Our model captures two distinct features arising from these fluctuations: magnon-assisted transport and the effect of spin-transfer torque on the magnetoconductance. The latter stems from magnetic misalignment in the junction induced by spin-current fluctuations. As the temperature is lowered, inelastic quantum scattering takes over thermal fluctuations, exhibiting signatures that make it readily distinguishable from magnon-assisted transport.

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Cited by in corpus (7)

• Quantum spin-transfer torque induced nonclassical magnetization dynamics and electron-magnetization entanglement
• Spintronics meets density matrix renormalization group: Quantum spin torque driven nonclassical magnetization reversal and dynamical buildup of long-range entanglement
• Quantum many-body states and Green functions of nonequilibrium electron-magnon systems: Localized spin operators vs. their mapping to Holstein-Primakoff bosons
• Energy and momentum conservation in spin transfer
• Effects of the dynamical magnetization state on spin transfer
• Quantum noise in the spin transfer torque effect
• Breaking of Coulomb blockade by macrospin-assisted tunneling