Gohlke Matthias, Verresen Ruben, Moessner Roderich, Pollmann Frank
Max-Planck-Institut für Physik komplexer Systeme, 01187 Dresden, Germany.
Department of Physics, T42, Technische Universität München, 85748 Garching, Germany.
Phys Rev Lett. 2017 Oct 13;119(15):157203. doi: 10.1103/PhysRevLett.119.157203. Epub 2017 Oct 12.
We introduce a matrix-product state based method to efficiently obtain dynamical response functions for two-dimensional microscopic Hamiltonians. We apply this method to different phases of the Kitaev-Heisenberg model and identify characteristic dynamical features. In the ordered phases proximate to the spin liquid, we find significant broad high-energy features beyond spin-wave theory, which resemble those of the Kitaev model. This establishes the concept of a proximate spin liquid, which was recently invoked in the context of inelastic neutron scattering experiments on α-RuCl_{3}. Our results provide an example of a natural path for proximate spin liquid features to arise at high energies above a conventionally ordered state, as the diffuse remnants of spin-wave bands intersect to yield a broad peak at the Brillouin zone center.
我们引入一种基于矩阵乘积态的方法，以有效地获得二维微观哈密顿量的动力学响应函数。我们将此方法应用于Kitaev - 海森堡模型的不同相，并识别其特征动力学特征。在接近自旋液体的有序相中，我们发现了超出自旋波理论的显著宽高能特征，这与Kitaev模型的特征相似。这确立了近邻自旋液体的概念，该概念最近在对α - RuCl₃的非弹性中子散射实验中被提及。我们的结果提供了一个例子，说明在高于传统有序态的高能处，近邻自旋液体特征出现的自然路径，即自旋波带的弥散残余相交，在布里渊区中心产生一个宽峰。
