Metal-Insulator Transition in 1T-TaS2: A Real-Space Dynamical Mean-Field Study

Much dispute remains as concerns the origin of the metal-insulator transition in layered compounds 1T-TaS2. Considering the disordered stacking of the atomic layers along the c-axis, we map the low-temperature phase of the transition metal dichalcogenide into a one-dimensional correlated system with the presence of disordered hopping integrals. To illustrate how the electronic correlations compete with the off-diagonal disorder, we employ the real-space dynamical mean-field theory to treat interactions and disorder on equal footing. We find that the Mott gap survives the strong off-diagonal disorder, which rules out the possibility of a metallic phase introduced by the disordered hoping integrals. Moreover, the lattice-size scaling of the generalized inverse participation ratio demonstrates that all electronic states are Anderson localized when the effect of disorder is being considered, and thus the optical conductivity shows insulating behavior for the bulk 1T-TaS2 compounds.