Fermi-liquid-like phase driven by next-nearest-neighbor couplings in a lightly doped kagome-lattice $t$-$J$ model

TL;DR

This study uses advanced computational methods to identify a Fermi-liquid-like phase in a lightly doped kagome-lattice $t$-$J$ model, driven by next-nearest-neighbor couplings, which exhibits suppressed charge order and enhanced correlations.

Contribution

The paper reveals a novel Fermi-liquid-like phase induced by next-nearest-neighbor interactions in the kagome $t$-$J$ model, supported by density matrix renormalization group calculations.

Findings

Emergence of a Fermi-liquid-like phase near charge density wave state.

Charge order is significantly suppressed in the new phase.

The phase persists at low doping levels on wider cylinders, indicating potential stability in 2D.

Abstract

Due to the interplay between charge fluctuation and geometry frustration, the doped kagome-lattice Mott insulator is a fascinating platform to realize exotic quantum states. Through the state-of-the-art density matrix renormalization group calculation, we explore the quantum phases of the lightly doped kagome-lattice $t$-$J$ model in the presence of the next-nearest-neighbor electron hopping $t_2$ and spin interaction $J_2$. On the $L_y = 3$ cylinder ($L_y$ is the number of unit cells along the circumference direction), we establish a quantum phase diagram with tuning $t_2 > 0$ and $J_2 > 0$, showing an emergent Fermi-liquid-like phase driven by increased $t_2$ and $J_2$, which sits at the neighbor of the previously identified charge density wave (CDW) phase. Compared with the CDW phase, the charge order is significantly suppressed in the Fermi-liquid-like phase, and most correlation functions are greatly enhanced with power-law decay. In particular, we find the absence of hole pairing and a strong three-sublattice magnetic correlation. On the wider $L_y = 4$ cylinder, this Fermi-liquid-like phase persists at low doping levels, strongly suggesting that this state might be stable in the two-dimensional kagome system.