DFT molecular dynamics and free energy analysis of a charge density wave surface system
Entity
UAM. Departamento de Física Teórica de la Materia CondensadaPublisher
Elsevier B.VDate
2019-06-15Citation
10.1016/j.apsusc.2019.02.020
Applied Surface Science 479 (2019): 260-264
ISSN
0169-4332 (print); 1873-5584 (online)DOI
10.1016/j.apsusc.2019.02.020Funded by
This work was supported by grant nos. MAT2014-59966-R and MAT2017-88258-R from the Ministerio de Economía, Industria y Competitividad (Spain)Project
Gobierno de España. MAT2014-59966-R; Gobierno de España. MAT2017-88258-REditor's Version
https://doi.org/10.1016/j.apcatb.2018.12.061Subjects
Alkali diffusion; Charge Density Wave; Density Functional Theory; Free energy; Molecular Dynamics; Mott insulator; FísicaNote
This Accepted Manuscript will be available for reuse under a CC BY-NC-ND licence after 24 months of embargo periodRights
© 2019 Elsevier B.V.Esta obra está bajo una licencia de Creative Commons Reconocimiento-NoComercial-SinObraDerivada 4.0 Internacional.
Abstract
The K/Si(111):B 3×3 surface, with one K atom per 3×3 unit cell, is considered a prototypical case of a surface Mott phase at room temperature. Our Density Functional Theory (DFT) Molecular Dynamics (MD) and free energy calculations show, however, a 23×3 Charge Density Wave (CDW) ground state. Our analysis shows that at room temperature the K atoms easily diffuse along the lines of a honeycomb network on the surface and that the 3×3 phase appears as the result of the dynamical fluctuations between degenerate CDW states. DFT-MD free energy calculations also show a 23×3↔3×3 transition temperature below 90 K. The competing electron-electron and electron-phonon interactions at low temperature are also analyzed; using DFT calculations, we find that the electron-phonon negative-U * is larger than the electron-electron Hubbard U, indicating that the CDW survives at very low temperature
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Google Scholar:Trabada, Daniel G.
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Mendieta Moreno, Jesús Ignacio
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Soler-Polo, Diego
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Flores Sintas, Fernando
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Ortega Mateo, José
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