Randomness induced spin-liquid-like phase in the spin-$1/2$ $J_1 - J_2$ triangular Heisenberg model

TL;DR

This study reveals that bond randomness in the spin-$1/2$ $J_1-J_2$ triangular Heisenberg model induces a gapless, spin-liquid-like phase characterized by the absence of magnetic, dimer, spin glass, or valence-bond glass order, with distinctive entanglement features.

Contribution

It demonstrates that bond randomness can induce a gapless spin-liquid-like phase in the triangular Heisenberg model, distinguishing it from the intrinsic spin liquid phase in the clean system.

Findings

Randomness induces a gapless spin-liquid-like phase.

The phase shows no magnetic, dimer, spin glass, or valence-bond glass order.

Entanglement spectrum features help distinguish the phase.

Abstract

We study the effects of bond randomness in the spin-$1/2$ $J_1-J_2$ triangular Heisenberg model using exact diagonalization and density matrix renormalization group. With increasing bond randomness, we identify a randomness induced spin-liquid-like phase without any magnetic order, dimer order, spin glass order, or valence-bond glass order. The finite-size scaling of gaps suggests the gapless nature of both spin triplet and singlet excitations, which is further supported by the broad continuum of dynamical spin structure factor. By studying the bipartite entanglement spectrum of the system on cylinder geometry, we identify the features of the low-lying entanglement spectrum in the spin-liquid-like phase, which may distinguish this randomness induced spin-liquid-like phase and the intrinsic spin liquid phase in the clean $J_1 - J_2$ triangular Heisenberg model. We further discuss the nature of this spin-liquid-like phase and the indication of our results for understanding spin-liquid-like materials with triangular-lattice structure.