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arXiv · 2203.02451

Mott Quantum Critical Points at finite doping

Maria Chatzieleftheriou·Alexander Kowalski·Maja Berović·Adriano Amaricci·Massimo Capone·Lorenzo De Leo·Giorgio Sangiovanni·Luca de' Medici
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Abstract

Strongly correlated materials often undergo a Mott metal-insulator transition, which is tipically first-order, as a function of control parameters like pressure. Upon doping, rich phase diagrams with competing instabilities are found. Yet, the conceptual link between the interaction-driven Mott transition and the finite-doping behavior lacks a clear connection with the theory of critical phenomena. In a prototypical case of a first-order Mott transition the surface associated with the equation of state for the homogeneous system is "folded" so that in a range of parameters stable metallic and insulating phases exist and are connected by an unstable metallic branch. Here we show that tuning the chemical potential the zero-temperature equation of state gradually unfolds. Under general conditions, we find that the Mott transition evolves into a first-order transition between two metals, associated to a phase separation region ending in a quantum critical point (QCP) at finite doping. This scenario is here demonstrated solving a simple multi-orbital Hubbard model relevant for the Iron-based superconductors, but its origin - the splitting of the atomic ground state multiplet by a small energy scale, here Hund's coupling - is much more general. A strong analogy with cuprate superconductors is traced.

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Maria Chatzieleftheriou, Alexander Kowalski, Maja Berović, Adriano Amaricci, Massimo Capone, Lorenzo De Leo, Giorgio Sangiovanni, Luca de' Medici. 2022-03-04. Mott Quantum Critical Points at finite doping. https://doi.org/10.1103/physrevlett.130.066401

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