Variation of the giant intrinsic spin Hall conductivity of Pt with carrier lifetime

Lijun Zhu; Lujun Zhu; Manling Sui; Daniel C Ralph; Robert A Buhrman

doi:10.1126/sciadv.aav8025

Variation of the giant intrinsic spin Hall conductivity of Pt with carrier lifetime

Sci Adv. 2019 Jul 19;5(7):eaav8025. doi: 10.1126/sciadv.aav8025. eCollection 2019 Jul.

Authors

Lijun Zhu¹, Lujun Zhu², Manling Sui³, Daniel C Ralph^{1

4}, Robert A Buhrman¹

Affiliations

¹ Cornell University, Ithaca, NY 14850, USA.
² College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China.
³ Institute of Microstructure and Property of Advanced Materials, Beijing University of Technology, Beijing 100124, China.
⁴ Kavli Institute at Cornell, Ithaca, NY 14853, USA.

Abstract

More than a decade after the first theoretical and experimental studies of the spin Hall conductivity (SHC) of Pt, both its dominant origin and amplitude remain in dispute. We report the experimental determination of the rapid variation of the intrinsic SHC of Pt with the carrier lifetime (τ) in the dirty-metal regime by incorporating finely dispersed MgO intersite impurities into the Pt, while maintaining its essential band structure. This conclusively validates the theoretical prediction that the SHC in Pt in the dirty-metal regime should be dominated by the intrinsic contribution, and should decrease rapidly with shortening τ. When interfacial spin backflow is taken into account, the intrinsic SHC of Pt in the clean limit is at least 1.6 × 10⁶ (ℏ/2e) ohm^-1 m^-1, more than 3.5 times greater than the available theoretical predictions. Our work also establishes a compelling spin Hall metal Pt_0.6(MgO)_0.4 with an internal giant spin Hall ratio of 0.73.