Intrinsic spin Hall effect in platinum: first-principles calculations

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• The spin Hall effect (SHE) is crucial for spintronics applications.
• Platinum is a significant material for studying metallic SHE.
• Understanding the origin of SHE in platinum is essential for device development.

Purpose of the Study:

• To investigate the spin Hall effect (SHE) in platinum using first-principles relativistic band calculations.
• To determine the intrinsic spin Hall conductivity (SHC) of platinum and its temperature dependence.
• To elucidate the microscopic mechanisms responsible for the large SHE in platinum.

Main Methods:

• First-principles relativistic band structure calculations.
• Analysis of spin-orbit splitting effects on electronic bands near the Fermi level.
• Modeling near-degeneracies with an effective Hamiltonian.

Main Results:

• Calculated intrinsic spin Hall conductivity (SHC) of platinum is approximately 2000(ħ/2πe)(Ω cm)⁻¹ at low temperatures, decreasing to 200(ħ/2πe)(Ω cm)⁻¹ at room temperature.
• Identified resonant contribution from spin-orbit splitting of d bands at L and X points near the Fermi level.
• Demonstrated that vertex corrections due to impurity scattering vanish, and SHC peaks near the Fermi energy.

Conclusions:

• The large spin Hall effect observed experimentally in platinum is predominantly of intrinsic origin.
• Spin-orbit splitting of specific electronic bands near the Fermi level is the primary cause of the high SHC.
• The findings support platinum's role as a key material in advanced spintronic devices.