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Title
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Probing charge density wave phases and the Mott transition in 1T-TaS₂I by inelastic light scattering
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Author
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Abstract
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| We present a polarization-resolved, high-resolution Raman scattering study of the three consecutive charge density wave (CDW) regimes in 1T-TaS2 single crystals, supported by ab initio calculations. Our analysis of the spectra within the low-temperature commensurate (C-CDW) regime shows P (3) over bar symmetry of the system, thus excluding the previously proposed triclinic stacking of the "star-of-David" structure, and promoting trigonal or hexagonal stacking instead. The spectra of the high-temperature incommensurate (IC-CDW) phase directly project the phonon density of states due to the breaking of the translational invariance, supplemented by sizable electron-phonon coupling. Between 200 and 352 K, our Raman spectra show contributions from both the IC-CDW and the C-CDW phases, indicating their coexistence in the so-called nearly commensurate (NC-CDW) phase. The temperature dependence of the symmetry-resolved Raman conductivity indicates the stepwise reduction of the density of states in the CDW phases, followed by a Mott transition within the C-CDW phase. We determine the size of the Mott gap to be Omega(gap) approximate to 170-190 meV, and track its temperature dependence. |
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Language
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English
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Source (journal)
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Physical review B / American Physical Society. - New York, N.Y, 2016, currens
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Publication
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New York, N.Y
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American Physical Society
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2021
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ISSN
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2469-9969
[online]
2469-9950
[print]
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DOI
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10.1103/PHYSREVB.103.245133
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Volume/pages
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103
:24
(2021)
, 10 p.
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Article Reference
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245133
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ISI
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000664450500002
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Medium
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E-only publicatie
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Full text (Publisher's DOI)
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Full text (open access)
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