Fundamental high pressure calibration from all-electron quantum Monte Carlo calculations
| Autor: | Burkhard Militzer, M. D. Towler, Richard J. Needs, Jeongnim Kim, Ronald E. Cohen, Kenneth Esler |
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| Jazyk: | angličtina |
| Rok vydání: | 2010 |
| Předmět: |
Physics
Equation of state Condensed Matter - Materials Science Phonon Quantum Monte Carlo Monte Carlo method Extrapolation General Physics and Astronomy Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences 3. Good health Pseudopotential Condensed Matter::Materials Science Ab initio quantum chemistry methods 0103 physical sciences Density functional theory Statistical physics 010306 general physics 0210 nano-technology |
| Popis: | We develop an all-electron quantum Monte Carlo (QMC) method for solids that does not rely on pseudopotentials, and use it to construct a primary ultra-high pressure calibration based the equation of state of cubic boron nitride(c-BN). We compute the static contribution to the free energy with QMC, and obtain the phonon contribution from density functional theory, yielding a high-accuracy calibration up to 900 GPa usable directly in experiment. Furthermore, we compute the anharmonic Raman frequency shift with QMC as a function of pressure and temperature, allowing optical pressure calibration in table-top experiments. In contrast to present experimental approaches, small systematic errors in the theoretical EOS do not increase with pressure, and no extrapolation is needed. This all-electron methodology is generally applicable to first-row solids, and can be used to provide a new reference for ab initio calculations of solids and to benchmark pseudopotential accuracy. 4 pages, 2 figures, 1 table |
| Databáze: | OpenAIRE |
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