HM-C21: A three-dimensional carbon with abundant p-electron-induced magnetic states for spintronics

Due to their long-distance spin transport and long spin lifetime, p-electron-induced spintronic materials have been attracting increasing attention. As the most common d-electron-free elements, carbon allotropes present many excellent properties. However, pure three-dimensional carbon spintronics material has not been reported so far. Here, we proposed a superhard (H_V = 60 GPa) carbon material named half-metal (HM)-C21, which presents multi-stable magnetic states and unexpected properties, such as those of half-metal, half-semiconductor, bipolar magnetic semiconductor, and asymmetric antiferromagnetic semiconductors. The mechanical, dynamical, and thermodynamical stabilities of HM-C21 are confirmed. Moreover, HM-C21 is considered to be a promising candidate for an unidentified cubic-form carbon reported in previous experiments. Hence, the present work holds great promise for discovering spintronic materials in pure three-dimensional carbon.