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arXiv · 1912.05669

Unveiling charge density wave quantum phase transitions by x-ray diffraction

F. B. Carneiro·L. S. I. Veiga·J. R. L. Mardegan·R. Khan·C. Macchiutti·A. Lopez·E. M. Bittar
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Abstract

We investigate the thermal-driven charge density wave (CDW) transition of two cubic superconducting intermetallic systems Lu(Pt1-xPdx)2In and (Sr1-xCax)3Ir4Sn13 by means of x-ray diffraction technique. A detailed analysis of the CDW modulation superlattice peaks as function of temperature is performed for both systems as the CDW transition temperature T_CDW is suppressed to zero by an non-thermal control parameter. Our results indicate an interesting crossover of the classical thermal-driven CDW order parameter critical exponent from a three-dimensional universality class to a mean-field tendency, as T_CDW vanishes. Such behavior might be associated with presence of quantum fluctuations which influences the classical second-order phase transition, strongly suggesting the presence of a quantum critical point (QCP) at T_CDW = 0. This also provides experimental evidence that the effective dimensionality exceeds its upper critical dimension due to a quantum phase transition.

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F. B. Carneiro, L. S. I. Veiga, J. R. L. Mardegan, R. Khan, C. Macchiutti, A. Lopez, E. M. Bittar. 2019-12-11. Unveiling charge density wave quantum phase transitions by x-ray diffraction. https://doi.org/10.1103/physrevb.101.195135

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