Ab initio study on heavy-fermion behavior in LiV${}_2$O${}_4$: Role of Hund's coupling and stability

LiV${}_2$O${}_4$ is a member of the so-called $3d$ heavy fermion compounds, with effective electron mass exceeding 60 times the free electron mass, comparable to $4f$ heavy fermion compounds. The origin of the strong electron correlation in combination with its metallic character have been a subject of intense theoretical and experimental discussion, with Kondo-like physics and Mott-physics being suggested as its physical origin. Here we report state-of-the art $\mathit{\text{ab}}\mathit{\text{initio}}$ Density Functional Theory + dynamical mean-field theory calculations for LiV${}_2$O${}_4$ for the full three orbital V $t_{2\mathrm{g}}$ manifold, and present temperature-dependent spectral properties. We map out the phase diagram for a representative 3-orbital model system as a function of doping and interaction strength, which indicates that LiV${}_2$O${}_4$ is located between two orbital-selective Mott phases, giving rise to a robust strongly correlated Hund’s metal behavior. At low temperature we find the emergence of a strongly renormalized sharp quasi-particle peak a few meV above the Fermi level of V $a_{1\mathrm{g}}$ character, in agreement with experimental reports.