Electric-Field Tunable THz Emission via Quantum Geometry in Dirac Semimetal

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Achieving nonvolatile control of spin degrees of freedom at terahertz (THz) frequencies is crucial for advanced spintronics.
• Current methods often require field cycling or remanent magnetization, limiting practical applications.

Purpose of the Study:

• To demonstrate all-electrical tunability of THz spintronic emission using the quantum geometry of a Dirac semimetal.
• To explore nonvolatile control of spin Hall conductivity at THz frequencies.

Main Methods:

• Utilized a heterobilayer structure combining a ferroelectric substrate with PtTe2 and a ferromagnetic material.
• Electrically modulated the Fermi level and Berry curvature of PtTe2 to control its spin Hall conductivity.
• Employed density functional theory (DFT) to corroborate experimental findings.

Main Results:

• Achieved a 21% modulation of THz emission amplitude through electrical control of PtTe2's spin Hall conductivity.
• Demonstrated nonvolatile tuning of THz spintronic emission under a constant magnetic field.
• DFT calculations confirmed doping-induced shifts in Berry curvature alter spin Hall conductivity.

Conclusions:

• Harnessing quantum geometry, specifically Berry curvature, enables efficient ultrafast spin-charge conversion.
• The developed approach offers a low-complexity, energy-efficient, and nonvolatile route for tunable spin Hall THz devices.
• Findings pave the way for novel applications of quantum geometry in spin-based logic and ultrafast electronics.