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Evidence for nesting-driven charge density wave instabilities in the quasi-two-dimensional material LaAgSb$_{2}$

Bosak, Alexeï; Souliou, Sofia-Michaela; Faugeras, Clément; Heid, Rolf; Molas, Maciej R.; Chen, Rong-Yan; Wang, Nan-Lin; Potemski, Marek; Le Tacon, Matthieu

Abstract (englisch):

Since their theoretical prediction by Peierls in the 1930s, charge density waves (CDWs have been one of the most commonly encountered electronic phases in low-dimensional metallic systems. The instability mechanism originally proposed combines Fermi surface nesting and electron-phonon coupling but is, strictly speaking, only valid in one dimension. In higher dimensions, its relevance is questionable as sharp maxima in the static electronic susceptibility χ(q) are smeared out, and is, in many cases, unable to account for the periodicity of the observed charge modulations. Here, we investigate the quasi-two-dimensional LaAgSb2, which exhibits two CDW transitions, by a combination of diffuse x-ray scattering, inelastic x-ray scattering, and ab initio calculations. We demonstrate that the CDW formation is driven by phonon softening. The corresponding Kohn anomalies are visualized in three dimensions through the momentum distribution of the x-ray diffuse scattering intensity. We show that they can be quantitatively accounted for by considering the electronic susceptibility calculated from a Dirac-like band, weighted by anisotropic electron-phonon coupling. ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000135107
Veröffentlicht am 07.07.2021
DOI: 10.1103/PhysRevResearch.3.033020
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Quantenmaterialien und -technologien (IQMT)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 07.2021
Sprache Englisch
Identifikator ISSN: 2643-1564
KITopen-ID: 1000135107
HGF-Programm 47.11.02 (POF IV, LK 01) Emergent Quantum Phenomena
Erschienen in Physical review research
Verlag American Physical Society (APS)
Band 3
Heft 3
Seiten Art.-Nr.: 033020
Bemerkung zur Veröffentlichung Gefördert durch den KIT-Publikationsfonds
Vorab online veröffentlicht am 06.07.2021
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