Emergent Fermi-Liquid-Like Phase by Melting a Holon Wigner Crystal in a Doped Mott Insulator on the Kagome Lattice

Abstract The doped quantum spin liquid on the kagome lattice provides a fascinating platform to explore exotic quantum states, such as the reported holon Wigner crystal at low doping. By extending the doping range to δ = 0.027–0.36, we studied the kagome-lattice t-J model using state-of-the-art density matrix renormalization group calculations. On the L_y = 3 cylinder (L_y is the number of unit cells along the circumferential direction), we established a quantum phase diagram with an increasing doping level. In addition to the charge density wave states at lower doping levels, we found an emergent Fermi-liquid-like phase by melting the holon Wigner crystal at δ ≈ 0.15, which is characterized by the suppression of charge density oscillation and power-law decay of various correlation functions. For a wider L_y = 4 cylinder, the bond-dimension extrapolated correlation functions also support such a Fermi-liquid-like state, suggesting its stability with increasing system size. In a narrow doping range near δ = 1/3 for the L_y = 3 cylinder, we find a state with an exponential decay of the single-particle correlation, but the other correlation functions preserve the features in the Fermi-liquid-like phase, which may be a precursor of a superconducting state. Nevertheless, this peculiar state near δ = 1/3 disappears for the L_y = 4 cylinder, implying a possible lattice-size dependence. Our results reveal quantum melting from a holon Wigner crystal to a Fermi-liquid-like state with increasing hole density and suggest a doping regime to explore superconductivity in future studies.