Predicting the temperature-strain phase diagram of VO$_2$ from first principles
Predicting the temperature-strain phase diagram of VO$_2$, including the various structural allotropes, from first principles is a grand challenge of materials physics, and even the phase diagram remains unclear at T = 0K. The coexistence of Peierls and Mott physics suggests that a theory which can...
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ndltd-columbia.edu-oai-academiccommons.columbia.edu-10.7916-D8KD3F902019-05-09T15:15:48ZPredicting the temperature-strain phase diagram of VO$_2$ from first principlesKim, Chanul2018ThesesPhysicsMaterials sciencePhase diagramsVanadium oxidePredicting the temperature-strain phase diagram of VO$_2$, including the various structural allotropes, from first principles is a grand challenge of materials physics, and even the phase diagram remains unclear at T = 0K. The coexistence of Peierls and Mott physics suggests that a theory which can capture strong electronic correlations will be necessary to compute the total energies. In order to understand the complex nature of the first-order transition of VO$_2$, we build a minimal model of the structural energetics using the Peirels-Hubbard model and solve it exactly using the Density Matrix Renormalization Group (DMRG) methods demonstrating that the on-site interaction $U$ has a minimal effect on the structural energetics for physical parameters. These results explain the qualitative failures of Density Functional Theory (DFT) and DFT+$U$ for the structural energetics, in addition to the partial success of the unorthodox DFT+$U$ results (i.e. non-spin-polarized and small $U$). It also guides the creation of empirical corrections to the DFT+$U$ functional which allow us to semi-quantitatively capture the phase stability of the rutile and monoclinic phases as a function of temperature and strain. Our work demonstrates that VO$_2$ is better described as a Mott assisted Peierls transition.Englishhttps://doi.org/10.7916/D8KD3F90 |
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NDLTD |
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English |
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Physics Materials science Phase diagrams Vanadium oxide |
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Physics Materials science Phase diagrams Vanadium oxide Kim, Chanul Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
description |
Predicting the temperature-strain phase diagram of VO$_2$, including the various structural allotropes, from first principles is a grand challenge of materials physics, and even the phase diagram remains unclear at T = 0K. The coexistence of Peierls and Mott physics suggests that a theory which can capture strong electronic correlations will be necessary to compute the total energies. In order to understand the complex nature of the first-order transition of VO$_2$, we build a minimal model of the structural energetics using the Peirels-Hubbard model and solve it exactly using the Density Matrix Renormalization Group (DMRG) methods demonstrating that the on-site interaction $U$ has a minimal effect on the structural energetics for physical parameters. These results explain the qualitative failures of Density Functional Theory (DFT) and DFT+$U$ for the structural energetics, in addition to the partial success of the unorthodox DFT+$U$ results (i.e. non-spin-polarized and small $U$). It also guides the creation of empirical corrections to the DFT+$U$ functional which allow us to semi-quantitatively capture the phase stability of the rutile and monoclinic phases as a function of temperature and strain. Our work demonstrates that VO$_2$ is better described as a Mott assisted Peierls transition. |
author |
Kim, Chanul |
author_facet |
Kim, Chanul |
author_sort |
Kim, Chanul |
title |
Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
title_short |
Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
title_full |
Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
title_fullStr |
Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
title_full_unstemmed |
Predicting the temperature-strain phase diagram of VO$_2$ from first principles |
title_sort |
predicting the temperature-strain phase diagram of vo$_2$ from first principles |
publishDate |
2018 |
url |
https://doi.org/10.7916/D8KD3F90 |
work_keys_str_mv |
AT kimchanul predictingthetemperaturestrainphasediagramofvo2fromfirstprinciples |
_version_ |
1719046913244790784 |