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Chaofan Gong

Publications and source records attributed to Chaofan Gong.

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Finite Temperature Dynamics of Spin Solitons with Applications in Thermocouples and Refrigerators

The exploitation of spin Berry phases to generate emergent fields for producing miniaturized and high-quality inductors has enjoyed considerable popularity among proponents of quantum technologies [Nature 586, 202 (2020)}]. Inspired by this breakthrough, we extend its mechanism to spin thermoelectrics by probing responses of ferrimagnetic domain walls (DWs) to thermal gradients. Similarly, voltages here stem from DW-spin collective motion, in contrast to normal electron transport phenomena. We further develop finite-temperature dynamics to investigate thermoelectric figures of merit and attribute corresponding quantum superiority to ultrafast spin evolution of ferrimagnetism with tunable non-Abelian phases. We propose a more likely cause of DW motion towards hot or cold regions (contrary to conclusions of previous reports) and verify existence of efficient magnon-momentum transfers. These findings deepen our understanding of heat-driven DW kinetics and suggest profitable new directions in an emerging realm of spincaloritronics.

cond-mat.other

Dynamics of Magnetic Skyrmions under Temperature Gradients

We expand the Zhang-Li spin-transfer torque [Phys. Rev. Lett. 93, 127204 (2004)] to finite temperatures by the scattering amplitude. Considering various factors including the adiabatic and diabatic effects of electrons and magnons, entropy equivalent field, thermal dipole field, thermal activation, magnetic-anisotropy gradient, and diffusion, we answer a recent question both experimentally and theoretically controversial: Will skyrmions move to the hot or cold region under thermal gradients?

cond-mat.other