Structure, property and magneto-optical interaction of wide-band-gap layered magnetism near the Néel temperature with antiferromagnetic to paramagnetic transition

Abstract

This work reports structural, optical, and vibrational behaviors, revealing the Néel ordering transformation of MnPS3 via temperature-dependent structure and optical measurements. In antiferromagnetic (AFM) state, MnPS3 exhibits high magnon-phonon coupling due to the ordered spin in the 3d orbital of the Mn2+ cation, which influences the intrinsic lattice and vibrational properties. The band-edge excitons of thin-layered MnPS3 were detected via micro-thermoreflectance (μTR) measurements at 20–300 K. When below the Néel temperature (TN = 78 K), MnPS3 exhibits two excitons, indicating the availability of a magnetic transition from the AFM to paramagnetic (PM) ordering. The direct-gap exciton of MnPS3 (E1OX) is at ∼ 2.632 eV at 300 K and it shifts to a higher energy of ∼ 2.846 eV at 20 K. With T < TN, an additional exciton (AMX) appeared at ∼ 0.16 eV lower than E1OX. It shows stronger at 20 K. The E1OX feature can be observed by μTR, and it shows an anomalous temperature-intensity change with the maximum amplitude at TN due to the spin-order transition from the AFM to the PM state. This work explores optical properties related to the magnetic transition of a wide-band-gap layered magnetism, which may be suitable for further magneto-optical device applications.