Possible nematic spin liquid in spin-1 antiferromagnetic system on the square lattice: Implications for the nematic paramagnetic state of FeSe

Abstract

The exotic normal state of iron chalcogenide superconductor FeSe, which exhibits vanishing magnetic order and possesses an electronic nematic order, triggered extensive explorations of its magnetic ground state. To understand its novel properties, we study the ground state of a highly frustrated spin-1 system with bilinearbiquadratic interactions using unbiased large-scale density matrix renormalization group. Remarkably, with increasing biquadratic interactions, we find a paramagnetic phase between Néel and stripe magnetic ordered phases. We identify this phase as a candidate of nematic quantum spin liquid by the compelling evidences, including vanished spin and quadrupolar orders, absence of lattice translational symmetry breaking, and a persistent non-zero lattice nematic order in the thermodynamic limit. The established quantum phase diagram natually explains the observations of enhanced spin fluctuations of FeSe in neutron scattering measurement and the phase transition with increasing pressure. This identified paramagnetic phase provides a new possibility to understand the novel properties of FeSe.

Gapless quantum spin liquid in a honeycomb Γ magnet

“…We would like to stress that the symmetry of Γ model itself is discrete and the asymmetrical boundary condition could cause instability on the landscape of bond energy, making it hard to determine the nematicity in the thermodynamic limit. However, the pending lattice nematicity does not alter our proposal of the QSL, because it could be accompanied by a broken lattice symmetry as reported in other theoretical models 61,62 . Despite such challenges, our work emphasizes on the inspiring and intractable quantum nature of the Γ model.…”

Quantum phase diagram of spin-1 J1−J2 Heisenberg model on the square lattice: An infinite projected entangled-pair state and density matrix renormalization group study

“…6(b), we show the finite-size scaling of σ 1 versus 1/L y . We should emphasize that although the cylinder geometry has already broken the lattice C 4 rotational symmetry, the size scaling has been shown, in different phases, to be an effective way for determining whether the nematic order would be finite or not in the large-size limit 30,31 .…”

“…Meanwhile, the frustrated spin-1 square Heisenberg models (SHM) are also typical for studying frustrated magnetism. Recently, the studies on the magnetism of the iron-based superconductors have drawn extensive interests in investigating the novel quantum phases, particularly the non-magnetic phase with lattice nematic order, in different spin-1 SHMs [21][22][23][24][25][26][27][28][29][30][31][32][33] . Among the various models, the spin-1 J 1 − J 2 SHM is probably the most fundamental model, which is defined as…”

Determining the anisotropy and exchange parameters of polycrystalline spin-1 magnets

“…Of particular relevance here are quasi-one-dimensional and quasi-two-dimensional systems based on S=1 magnetic moments, which inspire a great deal of contemporary theoretical attention (e.g. [1][2][3][4][5][6][7][8]) and are predicted to display vibrant phase diagrams arising from competing interactions and their interplay with singleion anisotropy. These diagrams encompass quantum critical points [1,2], nematic and supersolid states [5,9,10], as well as topologically interesting gapped and quantum paramagnetic phases [11][12][13][14].…”