Quantum phase transition between orbital-selective Mott states in Hund's   metals
  We report a quantum phase transition between orbital-selective Mott states, with different localized orbitals, in a Hund's metals model. Using the density matrix renormalization group, the phase diagram is constructed varying the electronic density and Hubbard $U$, at robust Hund's coupling. We demonstrate that this transition is preempted by charge fluctuations and the emergence of free spinless fermions, as opposed to the magnetically-driven Mott transition. The Luttinger correlation exponent is shown to have a universal value in the strong-coupling phase, whereas it is interaction dependent at intermediate couplings. At weak coupling we find a second transition from a normal metal to the intermediate-coupling phase. 
Julian Rincon, Adriana Moreo, Gonzalo Alvarez, and Elbio Dagotto
cond-mat.str-el cond-mat.mtrl-sci