Spin phonon interactions and magneto-thermal transport behavior in p-Si

Abstract

The spin-phonon interaction is the dominant process for spin relaxation in Si, and as thermal transport in Si is dominated by phonons, one would expect spin polarization to influence Si's thermal conductivity. Here we report the experimental evidence of just such a coupling. We have performed concurrent measurements of spin, charge, and phonon transport in p-doped Si across a wide range of temperatures. In an experimental system of a freestanding two um p-Si beam coated on one side with a thin (25 nm) ferromagnetic spin injection layer, we use the self-heating 3 omega method to measure changes in electrical and thermal conductivity under the influence of a magnetic field. These magneto-thermal transport measurements reveal signatures in the variation of electrical and thermal transport that are consistent with spin-phonon interaction. Raman spectroscopy measurements and first principle's calculations support that these variations are due to spin-phonon interaction. Spin polarization leads to softening of phonon modes, a reduction in the group velocity of acoustic modes, and a subsequent decrease in thermal conductivity at room temperature. Moreover, magneto-thermal transport measurements as a function of temperature indicate a change in the spin-phonon relaxation behavior at low temperature.

23 pages, 3 main figures, 4 supplemental figure

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Cited by in corpus (8)

• Chiral Phonon Induced Spin-Polarization
• Large spin-Hall effect in Si at room temperature
• Large Magnetic Moment in Flexoelectronic Silicon at Room Temperature
• Spin mediated magneto-electro-thermal transport behavior in Ni80Fe20/MgO/p-Si thin films
• Magnon-polaron formation in XXZ quantum Heisenberg chains
• Evidence of magnetoelectronic electromagnon mediated transport in flexoelectronic heterostructures
• Experimental evidence of hidden spin polarization in silicon by using strain gradient
• Interlayer charge transfer from contact electrification in conducting micro and nanoscale thin film heterostructures