Figure 5. Parametric plot of translational order t_trans against tetrahedrality order q_tetra for different temperatures from 1032 to 1800 K obtained from ab initio molecular dynamics simulations of liquid Si.

q_tetra and t_trans are not perfectly correlated in the structural anomaly region and with decreasing temperature, the correlation becomes weaker and weaker. Inset: The value of t_trans/q_tetra against pressure for different isotherms. Along the isotherm of T_c, t_trans/q_tetra is approximately linear with pressure, t_trans/q_tetra = 0.0015P + 0.494. With decreasing pressure along the isotherm below T_c, t_trans/q_tetra departs downward from the line until the LLPT occurs, while it is the opposite case above T_c.