A molecular diamond lattice antiferromagnet as a Dirac semimetal candidate

Abstract

The ground state of a molecular diamond-lattice compound (ET)Ag${}_4$(CN)${}_5$ is investigated by the magnetization and nuclear magnetic resonance spectroscopy. We found that the system exhibits antiferromagnetic long-range ordering with weak ferromagnetism at a high temperature of 102 K owing to the strong electron correlation. The spin susceptibility is well fitted into the diamond-lattice Heisenberg model with a nearest neighbor exchange coupling of 230 K, indicating the less frustrated interactions. The transition temperature elevates up to $\sim$195 K by applying pressure of 2 GPa, which records the highest temperature among organic molecular magnets. The first-principles band calculation suggests that the system is accessible to a three-dimensional topological semimetal with nodal Dirac lines, which has been extensively searched for a half-filling diamond lattice.

5 pages, 4 figures

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Cited by in corpus (1)

• A Monomer Mott Insulator (BEDT-TTF)Cu[N(CN)${}_2$]${}_2$ as a Potential Nodal Line System