Pressure-induced suppression of the Peierls distortion of liquid As and GeX (X=S,Se,Te)

The terminology ``Peierls distortion (PD)'' has been widely accepted in disordered systems ever since the discovery of PD in liquid As [R. Bellissent et al., Phys. Rev. Lett. 59, 661 (1987)]. It has not been clarified, however, to what extent the PD in liquids mirrors the PD in crystals. Here we report the observation on the pressure-induced suppression of PD in liquid As and liquid $\text{Ge}X$ $(X=\text{S},\text{Se},\text{Te})$, by which we clarified the qualitative differences as well as similarities between the PD of liquid and crystalline systems. By the appearance of prepeak that accompanies PD, we show that the intermediate-range order is related to the ``Peierls distortion'' in liquids, just as the Peierls distortion doubles the periodicity in one-dimensional lattice model.