Valiulin V E, Mikheyenkov A V, Chtchelkatchev N M, Barabanov A F
Institute for High Pressure Physics, Russian Academy of Sciences, Moscow (Troitsk) 108840, Russia. Department of Theoretical Physics, Moscow Institute of Physics and Technology (State University), Moscow 141700, Russia. National Research Centre 'Kurchatov Institute', Moscow 123182, Russia.
J Phys Condens Matter. 2019 Nov 13;31(45):455801. doi: 10.1088/1361-648X/ab35cc. Epub 2019 Jul 25.
Frustrated magnetic compounds, in particular low-dimensional, are topical research due to the persistent uncovering of novel nontrivial quantum states and potential applications. The problem of this field is that many important results are scattered over the localized parameter ranges, while areas in between still contain hidden interesting effects. We consider the [Formula: see text] Heisenberg model on the square lattice and use the spherically symmetric self-consistent approach for spin-spin Green's functions in 'quasielastic' approximation. We have found a new local order in spin liquids: antiferromagnetic isotropical helices. On the structure factor we see circular concentric dispersionless structures, while on any radial direction the excitation spectrum has 'roton' minima. That implies nontrivial magnetic excitations and consequences in magnetic susceptibility and thermodynamics. On the [Formula: see text] exchange parameters globe we discover a crossover between antiferromagnetic-like local order and ferromagnetic-like; we find stripe-like order in the middle. In fact, our 'quasielastic' approach allows investigation of the whole [Formula: see text] globe.
受挫磁性化合物，特别是低维的，由于不断发现新的非平凡量子态和潜在应用，成为热门研究领域。该领域的问题在于，许多重要结果分散在局部参数范围内，而其间区域仍包含隐藏的有趣效应。我们考虑正方晶格上的[公式：见正文]海森堡模型，并在“准弹性”近似下对自旋 - 自旋格林函数使用球对称自洽方法。我们在自旋液体中发现了一种新的局域序：反铁磁各向同性螺旋。在结构因子上，我们看到圆形同心无色散结构，而在任何径向方向上，激发谱都有“罗顿”极小值。这意味着非平凡的磁激发以及在磁化率和热力学方面的后果。在[公式：见正文]交换参数范围内，我们发现了类似反铁磁的局域序和类似铁磁的局域序之间的交叉；我们在中间发现了条纹状序。实际上，我们的“准弹性”方法允许对整个[公式：见正文]范围进行研究。
