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arXiv · 1302.1372

Non-universal shot noise in quasiequilibrium spin valves

T. T. Heikkila·K. E. Nagaev
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Abstract

We show that the breakdown of the Wiedemann-Franz law due to electron--electron scattering in diffusive spin valves may result in a strong suppression of the Fano factor that describes the ratio between shot noise and average current. In the parallel configuration of magnetizations, we find the universal value $\sqrt{3}/4$ in the absence of a normal-metal spacer layer, but including the spacer leads to a non-monotonous suppression of this value before reaching back to the universal value for large spacer lengths. On the other hand, in the case of an antiparallel configuration with a negligibly small spacer, the Fano factor is $\sqrt{3 (1-P^2)}/4$, where $P$ denotes the polarization of the conductivities. For $P\rightarrow \pm 1$, the current through the system is almost noiseless.

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T. T. Heikkila, K. E. Nagaev. 2013-02-06. Non-universal shot noise in quasiequilibrium spin valves. https://doi.org/10.1103/physrevb.87.235411

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