Orbitronics: the intrinsic orbital current in p-doped silicon

Area of Science:

• Condensed matter physics
• Spintronics
• Materials science

Background:

• The spin Hall effect (SHE) is a fundamental phenomenon in spintronics, crucial for spin-based electronics.
• SHE relies on spin-orbit coupling (SOC), which is typically weak in silicon, limiting its application.
• A need exists for alternative mechanisms to achieve spin-related transport phenomena in silicon.

Purpose of the Study:

• To investigate a novel dissipationless orbital current in p-doped silicon.
• To explore an effect analogous to the spin Hall effect but independent of strong intrinsic SOC.
• To demonstrate the robustness and detectability of this orbital Hall effect.

Main Methods:

• Theoretical modeling of charge and orbital transport in p-doped silicon under an electric field.
• Analysis of the role of impurity scattering and vertex corrections.
• Simulation of orbital momentum accumulation at sample edges.

Main Results:

• An electric field induces a dissipationless orbital current in p-doped silicon, mimicking the SHE.
• The orbital Hall effect (OHE) is robust against disorder as vertex corrections from impurity scattering vanish.
• Local orbital momentum accumulates at the sample edges, a direct consequence of the OHE.

Conclusions:

• The orbital Hall effect presents a viable alternative to the SHE in silicon-based spintronics.
• This effect's robustness against disorder makes it promising for practical device applications.
• The Kerr effect provides a feasible method for detecting the orbital Hall effect and its associated orbital momentum accumulation.