Ab initio molecular dynamics simulations on structural change of supercooled liquid Si at different temperatures from 1700 to 1100K

Liquid–Liquid Phase Transition in Nanoconfined Silicon Carbide

“…15 On this account, the LDL is nearly tetracoordinated with diamond-type structures, while the HDL is more highly coordinated and white-tin-like in nature. 10,13,16,17 The structural nature of the LDL and HDL determined by bonding species is consistent with the tetrahedrally bonded LDA with semiconductor features and the highly coordinated metallic HDA confirmed in refs 4 and 5. According to extensive numerical simulations, 10,18−20 based on the extrapolation of the LDA−HDA transition line, 3−5 the LDL and HDL in supercooled silicon are also separated by a line of first-order transition which, however, ends at a critical point with negative pressures in the temperature−pressure plane.…”

“…Sastry and Angell presented theoretical evidence using the Stillinger–Weber potential to support a first-order transition from a high-density liquid (HDL) to a low-density liquid (LDL) in the supercooled silicon at T ≈ 1060 K (at zero pressure), supported by subsequent experimental and simulation studies. − The coexistence of two completely different bonding species in liquid silicon, metallic and covalent, is believed to be a precondition for the LLPT. , The metallic bond nature favoring the isotropic symmetry would increase the density, while the covalent bond favoring the tetrahedral symmetry facilitates the lower density of LDL . On this account, the LDL is nearly tetracoordinated with diamond-type structures, while the HDL is more highly coordinated and white-tin-like in nature. ,,, The structural nature of the LDL and HDL determined by bonding species is consistent with the tetrahedrally bonded LDA with semiconductor features and the highly coordinated metallic HDA confirmed in refs and . According to extensive numerical simulations, ,− based on the extrapolation of the LDA–HDA transition line, − the LDL and HDL in supercooled silicon are also separated by a line of first-order transition which, however, ends at a critical point with negative pressures in the temperature–pressure plane.…”

Liquid-Liquid Phase Transition in Supercooled Silicon

“…The FPMD data was extracted from the reports of Stich el al. [44], Jakse et al [74], Colakogullari et al [106] and Wang et al [105]. We found experimental report of diffusion constant only at T m and we show them in our comparison.…”

“…2. Both ab initio and SW simulations have the first minimum of g(r) at around 3 Å (except for Wang et al [105] which shows the first minimum of g(r) to be at 3.3 Å).…”