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

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