Topological evolution of correlated band structures and heavy-fermion-like behavior in a molybdenum-based metal organic framework C48S36Mo6

Abstract

Owing to the fascinating properties of two dimensional transition metal dichalcogenides and the stability of ZIF-8 as the subclass of metal organic frameworks (MOFs), we propose a Mo-based MOFs material C48S36Mo6 containing organic ligands connecting to each other by Mo4+ metal ions. We reveal heavy-fermion-like electronic behaviour that results from highly localized impurity-like Mo-d electrons and tiny energy difference (<0.4 meV/atom) between antiferromagnetic and ferromagnetic state, using the generalized gradient approximation and its combination with Coulomb correlation U. Considering thermal fluctuation and weak magnetic exchange energy, C48S36Mo6 is a nonmagnetic metal at room temperature, and magnetic insulator at low temperature with a correlation-driven metal–insulator transition. Our Wannier functions analysis indicates that topological properties of energy bands around the Fermi level can be perturbed by correlation U, leading to moving of close nodal lines in three dimensional momentum space. Further introducing of spin–orbit coupling opens a small inverted energy gap of 3 meV at original nodal line due to bulk inversion symmetry. If a gate voltage of 48 meV is applied, the Fermi level will fall into the small energy gap of band inversion, and the system will realize a phase transition from Kondo metal to topological Kondo insulator.