Resolving the chicken-and-egg problem in VO2

Outline

• Solve using DMFT a reference model: The Dimer Hubbard Model
• Characterize the correlated Insulator to correlated Metal transition
• Dimer-Mott Transition explains key experiments in the transition of VO2

Dynamical Mean Field Theory (DMFT)

• Same cluster impurity problem as other LDA+DMFT studies for VO2
• Solved Exactly in the Bethe Lattice
• DMFT Exact by construction in the large coordination limit
• DMFT yields generic behavior of a high-dimensional lattice

Reference Mott transition: V$$_2$$O3

The case $$t_\perp/D=0$$ no dimers

The Dimer-Mott transition: VO2

The dimerized $$t_\perp/D=0.3$$ lattice

Conclusions

• The Dimer Hubbard Model describes a temperature driven insulator to metal correlated transition
• These results explain key observations in the transition in VO2: the Mid-Infrared features in the optical conductivity before the structural transition takes place
• The existence of a metastable correlated dimer metal phase is the key ingredient that shows that the VO2 Insulator Metal transition is electronically driven(Dimer Mott Mechanism)
• Read more about our work in: O. Nájera, et al. (2017). PRB, 95(3), 035113