Fig. 4
From: Dimensional crossover in a layered ferromagnet detected by spin correlation driven distortions
Hyper-polarizable bond model and dimensional crossover. Plots show hyper-polarizable bond model calculations of the change in each of the eight allowed SHG susceptibility tensor elements relative to their undistorted values (\({\mathrm{\Delta }}\chi _{ijkl}\)) under totally symmetric distortions along the a, \(A_g^1\), b, \(A_g^2\), c, \(A_g^3\) and d, \(A_g^4\) normal coordinates. Schematics in the insets show the bonds (springs) used in our model and depict how each distortion is parameterized. Both vertical and horizontal axes are plotted on a linear scale. Tensor elements that change in the same way are represented as multi-colored curves. e Illustration of the spin ordering process in CrSiTe3 deduced from our data. The light blue regions represent an absence of spin-spin correlations and the dark blue regions represent FM correlations, which are dynamic above Tc and static below Tc
