Orbital Diffusion, Polarization, and Swapping in Centrosymmetric Metals.

Area of Science:

• Condensed matter physics
• Quantum mechanics

Background:

• Understanding charge, spin, and orbital dynamics is crucial for novel electronic devices.
• Existing theories often lack a unified framework for these transport phenomena.

Purpose of the Study:

• To propose a general theory for charge, spin, and orbital diffusion.
• To investigate the distinct transport properties of orbital angular momentum.

Main Methods:

• Utilizing the Keldysh formalism.
• Developing a theoretical framework for coupled charge, spin, and orbital transport.

Main Results:

• Orbital angular momentum diffusivity is significantly lower than spin or charge diffusivity in metals due to orbital intermixing.
• Introduced "spin-orbit polarization": pure orbital currents induce longitudinal spin currents, and vice versa, with high efficiency.
• Observed momentum swapping in orbital currents, even without spin-orbit coupling.

Conclusions:

• The developed theory provides a unified understanding of charge, spin, and orbital transport.
• Identified key parameters governing orbital transport, crucial for experimental advancements.