Using the bosonization approach we study fermionic systems with a nonlinear dispersion relation in dimension d>2. We explicitly show how the band curvature gives rise to interaction terms in the bosonic version of the model. Although these terms are perturbatively irrelevant in relation to the Landau Fermi liquid fixed point, they become relevant perturbations when instabilities take place. Using a coherent state path integral technique we built up the effective action that governs the dynamics of the Fermi surface fluctuations. We consider the combined effect of fermionic interactions and band curvature on possible anisotropic phases triggered by negative Landau parameters. In particular we study in some detail the phase diagram for the isotropic/nematic/hexatic quantum phase transition.
Energy-dependent crossover from anisotropic to isotropic magnetic dispersion in lightly-doped La1.96Sr0.04CuO4
对轻掺杂La $_{1.96}$ Sr $_{0.04}$ CuO $_{4}$进行了非弹性中子散射实验，发现低温下存在对角非公度自旋关联.我们以前报道过，这种晶体，与一个单一的斜方晶域，表现出“沙漏”分散在低能量[物理评论快报。101，197001（2008）]。在本文中，我们详细调查的能量演化的磁激发高达65毫电子伏。结果发现，在低能量的各向异性激发，仅沿自旋调制方向分散，交叉到各向同性，圆锥形的分散体，类似于在母体化合物La $_2$ CuO $_{4}$的自旋波。从两重到完全对称的变化跨越沙漏的腰部再现的行为首先在欠掺杂的YBa $_2$ Cu $_3$ O $_{6+x}$的研究中确定。我们讨论了这些结果的意义。
Thermal and Magnetoelastic Properties of the van der Waals Ferromagnet Fe$_{3-δ}$GeTe$_2$: Anisotropic Spontaneous Magnetostriction and Ferromagnetic Magnon Excitations
Magnetic-field dependence of low-energy magnons, anisotropic heat conduction, and spontaneous relaxation of magnetic domains in the cubic helimagnet ZnCr2Se4
Spin-Wave and Electromagnon Dispersions in Multiferroic MnWO4 as Observed by Neutron Spectroscopy: Isotropic Heisenberg Exchange versus Anisotropic Dzyaloshinskii-Moriya Interaction
Instability of the Luttinger liquids towards an exotic quantum state of matter with highly degenerate ground states: an anisotropic extension of the ferromagnetic spin-1 biquadratic model
