Canted spin states and thermal spin crossover behavior in p-Si

P. C. Lou, W. P. Beyermann, S. Kumar

Published 2017-01-26Version 1

Recent work on spin mediated thermal transport in semiconductor materials has led to the discovery of the spin Hall effect in p-Si. Spin accumulation may change the electro-thermal transport within the material, and thus may serve as an investigative tool for characterizing spin-mediated behavior. In Si, spin-phonon interaction is the primary spin relaxation mechanism. The absence of spin-phonon relaxation will create coherent spin states due to spin accumulation. Here we present the first experimental proof of spin accumulation induced coherent canted spin states in non-magnetic p-Si. Using magneto-thermal transport measurements, we show effect of spin accumulation due to the spin Hall effect on thermal conductivity of a p-Si specimen at low temperatures. The temperature-dependent V3{\omega} measurement shows hysteretic thermal spin crossover behavior attributed to antiferromagnetic spin-spin interactions and spin-phonon interactions. The canted spin states originate from the antiferromagnetic interactions in p-Si, which is validated from the spin relaxation behavior in magnetoresistance measurement. The relaxation of canted spin states generates a giant spin current leading to switching of Ni80Fe20 layer. The switching behavior can provide an energy efficient mechanism for spintronics memory devices. This result opens a new paradigm in the field of spin-mediated semiconductor spintronics and antiferromagnetic spintronics.