Cohesion and excitations of diamond-structure silicon by quantum Monte Carlo: Benchmarks and control of systematic biases
| Autor: | M. Chandler Bennett, Cody A. Melton, Abdulgani Annaberdiyev, Guangming Wang, Lubos Mitas |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Physics
Condensed Matter - Materials Science Band gap Quantum Monte Carlo Fermi level Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences 02 engineering and technology Electronic structure Computational Physics (physics.comp-ph) 021001 nanoscience & nanotechnology 01 natural sciences symbols.namesake Excited state 0103 physical sciences Quasiparticle symbols Atomic physics 010306 general physics 0210 nano-technology Wave function Ground state Physics - Computational Physics |
| DOI: | 10.48550/arxiv.2102.11998 |
| Popis: | We have carried out quantum Monte Carlo (QMC) calculations of silicon crystal focusing on the accuracy and systematic biases that affect the electronic structure characteristics. The results show that 64 and 216 atom supercells provide an excellent consistency for extrapolated energies per atom in the thermodynamic limit for ground, excited, and ionized states. We have calculated the ground state cohesion energy with both $\textit{systematic and statistical errors}$ below $\approx$0.05 eV. The ground state exhibits a fixed-node error of only $1.3(2)\%$ of the correlation energy, suggesting an unusually high accuracy of the corresponding single-reference trial wave function. We obtain a very good agreement between optical and quasiparticle gaps that affirms the marginal impact of excitonic effects. Our most accurate results for band gaps differ from the experiments by about 0.2 eV. This difference is assigned to a combination of residual finite-size and fixed-node errors. We have estimated the crystal Fermi level referenced to vacuum that enabled us to calculate the edges of valence and conduction bands in agreement with experiments. Comment: Peer-reviewed version |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|