Dirac Charge in Antiferromagnetic Topological Semimetals

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Topological nodes in electronic band structures exhibit emergent charge degrees of freedom, such as Berry curvature monopoles in Weyl semimetals.
• These phenomena lead to unique transport and optical properties in topological materials.

Purpose of the Study:

• To investigate the existence of a hidden
• Dirac charge
• in antiferromagnetic (AFM) Dirac semimetals.
• To demonstrate a method for detecting this Dirac charge via photocurrent response.
• To reveal novel properties associated with Dirac points in AFM Dirac semimetals.

Main Methods:

• Definition of Berry curvature in a generalized spin and spin-charge-mixed parameter space.
• Identification of Dirac charges as sources or sinks of Berry curvature.
• Real-time simulations to analyze photocurrent generation driven by spin-charge-coupled motive force.

Main Results:

• Dirac charges are identified as sources or sinks of Berry curvature in the generalized parameter space.
• The Dirac charge is detectable through photocurrent generated by a spin-charge-coupled motive force.
• Real-time simulations confirm the significant role of Dirac charge in photocurrent generation within AFM Dirac semimetals.

Conclusions:

• This study reveals the existence and detectability of a hidden Dirac charge in AFM Dirac semimetals.
• The photocurrent response serves as a viable method for detecting this emergent charge degree of freedom.
• The findings shed light on the fundamental properties of Dirac points in antiferromagnetic topological materials.