TY - JOUR
T1 - Assessing the accuracy of compound formation energies with quantum Monte Carlo
AU - Isaacs, Eric B.
AU - Shin, Hyeondeok
AU - Annaberdiyev, Abdulgani
AU - Wolverton, Chris
AU - Mitas, Lubos
AU - Benali, Anouar
AU - Heinonen, Olle
N1 - Publisher Copyright:
© 2022 American Physical Society.
PY - 2022/6/1
Y1 - 2022/6/1
N2 - Accurately predicting the formation energy of a compound, which describes its thermodynamic stability, is a key challenge in materials physics. Here, we employ a many-body quantum Monte Carlo (QMC) with single-reference trial functions to compute the formation energy of two electronically disparate compounds, the intermetallic VPt2 and the semiconductor CuI, for which standard density functional theory (DFT) predictions using both the Perdew-Burke-Ernzerhof (PBE) and the strongly constrained and appropriately normed (SCAN) density functional approximations deviate markedly from available experimental values. For VPt2, we find an agreement between QMC, SCAN, and PBE0 estimates, which therefore remain in disagreement with the much less exothermic experimental value. For CuI, the QMC result agrees with neither SCAN nor PBE pointing towards DFT exchange-correlation biases, likely related to the localized Cu 3d electrons. Compared to the behavior of some density functional approximations within DFT, spin-averaged QMC exhibits a smaller but still appreciable deviation when compared to experiment. The QMC result is slightly improved by incorporating spin-orbit corrections for CuI and solid I2, so that experiment and theory are brought into imperfect but reasonable agreement within about 120 meV/atom.
AB - Accurately predicting the formation energy of a compound, which describes its thermodynamic stability, is a key challenge in materials physics. Here, we employ a many-body quantum Monte Carlo (QMC) with single-reference trial functions to compute the formation energy of two electronically disparate compounds, the intermetallic VPt2 and the semiconductor CuI, for which standard density functional theory (DFT) predictions using both the Perdew-Burke-Ernzerhof (PBE) and the strongly constrained and appropriately normed (SCAN) density functional approximations deviate markedly from available experimental values. For VPt2, we find an agreement between QMC, SCAN, and PBE0 estimates, which therefore remain in disagreement with the much less exothermic experimental value. For CuI, the QMC result agrees with neither SCAN nor PBE pointing towards DFT exchange-correlation biases, likely related to the localized Cu 3d electrons. Compared to the behavior of some density functional approximations within DFT, spin-averaged QMC exhibits a smaller but still appreciable deviation when compared to experiment. The QMC result is slightly improved by incorporating spin-orbit corrections for CuI and solid I2, so that experiment and theory are brought into imperfect but reasonable agreement within about 120 meV/atom.
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U2 - 10.1103/PhysRevB.105.224110
DO - 10.1103/PhysRevB.105.224110
M3 - Article
AN - SCOPUS:85133512262
SN - 2469-9950
VL - 105
JO - Physical Review B
JF - Physical Review B
IS - 22
M1 - 224110
ER -