New Ab Initio Based Pair Potential for Accurate Simulation of Phase Transitions in ZnO

Abstract

A set of interatomic pair potentials is developed for ZnO based on the partially charged rigid ion model (PCRIM). The derivation of the potentials combines lattice inversion, empirical fitting, and ab initio energy surface fitting. We show that, despite the low number of parameters in this model (8), a wide range of physical properties is accurately reproduced using the new potential model. The calculated lattice parameters and elastic constants of ZnO in the wurtzite (WZ) phase, as well as the lattice parameters and stabilities of ZnO in other high-pressure and metastable phases, agree well with experiments and with density functional theory (DFT) calculations. The calculated transition pressure of the wurtzite-to-rocksalt (WZ-to-RS) transition is 12.3 GPa. A wurtzite-to-honeycomb (WZ-to-HC) phase transition induced by uniaxial pressure along the c-axis is simulated by means of molecular dynamics (MD) simulations. The WZ-to-HC transition takes place at an uniaxial pressure of 8.8 GPa while the reverse transition takes place at 2.9 GPa, which is consistent with DFT calculations. Other physical properties, including phonon dispersion, phonon density of states, and melting point calculated using our ZnO potential model are in good agreement with experimental and DFT data. Limitations of the novel ZnO potential model are also discussed.

Understanding the tensile behaviors of ultra-thin ZnO nanowires via molecular dynamics simulations

“…The parameters A, ρ and C are obtained by empirical fitting to the structure and properties of WZ-structured ZnO, 20 as listed in After geometric construction, we performed a series of relevant MD simulations. During the process of simulation, NPT conditions using the Nose-Hoover thermostat were imposed in the system.…”

Comparison of three empirical force fields for phonon calculations in CdSe quantum dots

“…These have been employed chiefly in molecular dynamics simulations of processes such as surface reconstruction and phase transitions, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] but there has also been interest in using empirical potentials to calculate the geometries and vibrations of semiconductor nanocrystals ("quantum dots" when nearly spherical). [20][21][22][23][24][25][26][27][28] Our group has been using quantitative resonance Raman intensity analysis to probe electron-phonon coupling in 4 CdSe-containing quantum dots (QDs), [29][30][31][32][33] and full interpretation of these data requires knowledge of the phonon frequencies and modes.…”

A transferable force field for CdS-CdSe-PbS-PbSe solid systems

“…30,[33][34][35][36][37][38] However, to simulate NCs containing more than a few thousands of atoms, DFT calculations are no longer possible because of the huge computational demands. Instead, classical molecular simulations techniques such as molecular dynamics (MD) or Monte Carlo (MC) using classical force fields are more commonly used to deal with large systems.…”

“…The use of integer charges in force fields of ionic solid materials helps their transferability and enables modelling of the energy and local structure of defects in the materials. [45][46][47][48] However, there is also evidence that force fields developed for ionic solids using partial charges 33,39,49 have superior performance to those using integer charges 42,50,51 for reproducing physical properties such as lattice parameters, elastic constants, and phase stabilities; (2) Three-body and four-body interatomic interaction potentials were used in this SM to stabilize the tetrahedrally coordinated structure of CdS and ZnS. Three-body interatomic interaction potentials are often used to describe the directional feature of the covalent bonds.…”