Active ballistic orbital transport in Ni/Pt heterostructure

Area of Science:

• Solid-state physics
• Quantum information technology
• Materials science

Background:

• Orbital current, the orbital character of Bloch states, offers advantages in coherence length over spin current.
• Active control of orbital transport is crucial for advancing quantum information technology.
• Orbital angular momentum couples efficiently to phonon angular momentum via orbital-crystal momentum (L-k) coupling.

Purpose of the Study:

• To experimentally demonstrate the active control of orbital current velocity.
• To investigate the mechanisms of orbital transport in Ni/Pt heterostructures.
• To explore the potential of optorbitronics for information transmission.

Main Methods:

• Utilizing the orbital-dependent L-k coupling for control.
• Experimental demonstration in Ni/Pt heterostructures.
• Observation of terahertz (THz) emission via long-range ballistic orbital transport.

Main Results:

• Observed THz emission correlated with Pt thickness, indicating long-range ballistic orbital transport.
• Identified a critical energy density threshold for overcoming collisions in orbital transport.
• Demonstrated femtosecond light-driven active control of ballistic orbital transport.

Conclusions:

• Active control of orbital current velocity is achievable in Ni/Pt heterostructures.
• Orbital transport enables efficient information transmission with potential for dynamic optorbitronics.
• Findings lay the groundwork for developing next-generation information transmission technologies.