Speaker
Description
Antiferromagnets with spin-split bands in the momentum space emerged as promising materials for technologies based on antiferromagnetic spintronics using spin-orbit or spin-splitting torque. The absence of bulk or structural inversion symmetry along with spin-orbit interaction leads to such spin-splitting known as Dresselhaus or Rashba effect, respectively. Spin-splitting phenomena occur even for compounds with low atomic numbers in the absence of combined inversion | time reversal and combined spin rotation | translation symmetries [1]. We identify a centrosymmetric material MnTe that exhibits both types of spin-splitting phenomena, making it interesting to study. Using a carefully chosen exchange-correlation functional and corrections, our calculations within density functional theory reveal an insulating state with a preferred antiferromagnetic order. To look into the magnetic behavior in detail, we have computed different exchange interaction strengths and estimated the magnetic ordering temperature via Monte Carlo calculations. Our calculation and symmetry analysis reveals a large spin-splitting in the system due to the antiferromagnetic order without considering spin-orbit interaction, except in the kx-ky plane. Critical examination of the band dispersion and the spin textures obtained from our calculation and a comparison with an insightful analytical model confirms the presence of a combined Rashba-Dresselhaus interaction around the high-symmetry K point in the kx-ky plane [2]. Further, we investigate the ferroelectric property of this system and find reasonable electric polarization in a higher-energy magnetic configuration. Our investigation uncovers the spin-splitting phenomena with and without spin-orbit coupling, making it a promising candidate for technological applications.
[1] L. D. Yuan, Z. Wang, J. W. Luo, E. I. Rashba, and A. Zunger, Giant momentum-dependent spin splitting in centrosymmetric low-Z antiferromagnets, Physical Review B 102, 14422 (2020).
[2] S. Rooj, J. Chakraborty, and N. Ganguli, Antiferromagnetism, spin splitting, and spin-orbit interaction in MnTe, arXiv:2301.07985.
