engleski

Large spin Hall effect induced by resonant scattering on spin-orbit split impurity states

We present experimental results which show that doping Cu with (nonmagnetic) 6d impurities can induce a very large Spin Hall Effect. The Spin Hall conductivity can exceed 10^7 Ohm^(-1)m^(-1), to be compared to 10^4-10^6 Ohm^(-1)m^(-1) in Pt or Au (Kimura et al, PRL 2007 ; Seki et al, Nature Materials ; 2008), 10^3 Ohm^(-1)m^(-1) in Al (Valenzuela and Tinkham, Nature 2006) or 1 Ohm^(-1)m^(-1) in InGaAs (Kato et al, Science 2004). Resonant skew scattering on spin-orbit split impurity states explains the large value of the SHE induced by nonmagnetic impurities like Ir, Ta, Lu or Sb. It also explains that the different signs of the SHE we observe at the beginning (Lu) and end (Ir) of the 5d series are related to the position of the resonant 5d states with respect to the Fermi level. We will present a theoretical model of resonant skew scattering accounting for our results and discuss the advantage of resonant scattering on other mechanisms. An extension to resonant side-jump scattering will be also presented.

spin Hall efect; spin-orbit interaction; resonant scattering; spintronics

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