Modulation of energy and angular momentum radiation of two-dimensional altermagnets

This paper investigates the energy and angular momentum radiation of altermagnets under Rashba spin-orbit coupling (RSOC) and external magnetic fields. Using an effective low-energy Hamiltonian, we derive electronic energy bands and calculate optical conductivity via the Kubo formula. Results show that RSOC strength, altermagnet interactions strength, and N\'eel vector direction notably affect the optical conductivity of altermagnet metals. Energy radiation is highly sensitive to Rashba spin-orbit coupling, with a saturation effect beyond a particular value, and its peak emission rate is lower than that of graphene due to reduced conductivity. Different from usual semiconductor, semimetal, or Dirac materials, e.g., graphene or silicene, altermagnets generate angular momentum radiation with specific Rashba spin-orbit coupling and altermagnet interaction strength. Angular momentum radiation is minimally reactive to Rashba spin-orbit coupling at low altermagnet interactions strength values but exhibits drastic oscillations between extreme values as altermagnet interactions strength reaches a critical point, showing high sensitivity. These findings suggest that adjusting these parameters can tailor altermagnet applications in spintronics and quantum technologies, potentially leading to innovative devices with customized radiation attributes.