Rhombohedral Lanthanum Manganite: A New Class of Dirac Half-Metal with Promising Potential in Spintronics

Dirac half-metals have drawn great scientific interests in spintronics because of their outstanding physical properties such as the large spin polarization and massless Dirac fermions. By using first-principles calculations, we investigate the perovskite-type lanthanum manganite (LaMnO₃) as a novel Dirac half-metal. Specifically, LaMnO₃ displays multiple linear band crossings in the spin-up direction, while it has a large band gap (∼5 eV) in the spin-down orientation. The intriguing linear band dispersions guarantee the ultrafast electron transport and the significant band differences between spin up and down directions promise the realization of 100% spin-polarized current and the extremely low energy consumption. Such a spin-polarized Dirac material is rare among perovskite-type compounds. By adopting the mean-field theory, the estimated Curie temperature T_c is 438.4 K. Importantly, the LaMnO₃ crystal has been experimentally realized 2 decades ago, which facilitates the future experimental validation. With the novel spin-polarized electronic properties and the high possibility of experimental fabrication, LaMnO₃ is ideal for the spintronic application.