Competition between Superconductivity and Charge Density Wave Ordering in the Lu$_5$Ir$_4$(Si$_{1-x}$Ge$_x$)$_{10}$ Alloy System

Yogesh Singh; R. Nirmala; S. Ramakrishnan; S. K. Malik

doi:10.1103/PhysRevB.72.045106

paper

Competition between Superconductivity and Charge Density Wave Ordering in the Lu $_{5}$ Ir $_{4}$ (Si $_{1 - x}$ Ge $_{x}$ ) $_{10}$ Alloy System

arXiv:cond-mat/0505463 · doi:10.1103/PhysRevB.72.045106

Abstract

We have performed bulk measurements such as dc magnetic susceptibility, electrical resistivity and heat capacity on the pseudo-ternary alloys Lu $_{5}$ Ir $_{4}$ (Si $_{1 - x}$ Ge $_{x}$ ) $_{10}$ to study the interplay and competition between superconductivity and the charge density wave (CDW) ordering transition. We track the evolution of the superconducting transition temperature T $_{S C}$ and the CDW ordering temperature T $_{C D W}$ as a function of x (concentration of Ge) ( $0.0 \leq x \leq 1.0$ ). We find that increasing x (increasing disorder) suppresses the T $_{C D W}$ rapidly with the concomitant increase in T $_{S C}$ . We present a temperature-concentration (or volume) phase diagram for this system and compare our results with earlier work on substitution at the Lu or Ir site to show how dilution at the Si site presents a different situation from these other works. The heat capacity data in the vicinity of the CDW transition has been analyzed using a model of critical fluctuations in addition to a mean-field contribution and a smooth lattice background. We find that the critical exponents change appreciably with increasing disorder. This analysis suggests that the strong-coupling and non mean-field like CDW transition in the parent compound Lu $_{5}$ Ir $_{4}$ Si $_{10}$ changes to a mean-field like transition with increasing Ge concentration.

arXiv comment14 pages and 8 figures. Accepted for publication in Phys. Rev. B

Competition between Superconductivity and Charge Density Wave Ordering in the Lu5​Ir4​(Si1−x​Gex​)10​ Alloy System

Abstract

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Competition between Superconductivity and Charge Density Wave Ordering in the Lu $_{5}$ Ir $_{4}$ (Si $_{1 - x}$ Ge $_{x}$ ) $_{10}$ Alloy System