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arXiv · 1101.3516

Competing charge density waves and temperature-dependent nesting in 2H-TaSe2

Ph. Leininger·D. Chernyshov·A. Bosak·H. Berger·D. S. Inosov
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Abstract

Multiple charge density wave (CDW) phases in 2H-TaSe2 are investigated by high-resolution synchrotron x-ray diffraction. In a narrow temperature range immediately above the commensurate CDW transition, we observe a multi-q superstructure with coexisting commensurate and incommensurate order parameters, clearly distinct from the fully incommensurate state at higher temperatures. This multi-q ordered phase, characterized by a temperature hysteresis, is found both during warming and cooling, in contrast to previous reports. In the normal state, the incommensurate superstructure reflection gives way to a broad diffuse peak that persists nearly up to room temperature. Its position provides a direct and accurate estimate of the Fermi surface nesting vector, which evolves non-monotonically and approaches the commensurate position as the temperature is increased. This behavior agrees with our recent observations of the temperature-dependent Fermi surface in the same compound [Phys. Rev. B 79, 125112 (2009)].

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Ph. Leininger, D. Chernyshov, A. Bosak, H. Berger, D. S. Inosov. 2011-01-18. Competing charge density waves and temperature-dependent nesting in 2H-TaSe2. https://doi.org/10.1103/physrevb.83.233101

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