Infrared study of valence transition compound YbInCu4 using cleaved surfaces

Abstract

Optical reflectivity R(w) of YbInCu4 single crystals has been measured across its first-order valence transition at T_v ~ 42 K, using both polished and cleaved surfaces. R(w) measured on cleaved surfaces Rc(w) was found much lower than that on polished surface Rp(w) over the entire infrared region. Upon cooling through T_v, Rc(w) showed a rapid change over a temperature range of less than 2 K, and showed only minor changes with further cooling. In contrast, Rp(w) showed much more gradual and continuous changes across T_v, similarly to previously reported data on polished surfaces. The present result on cleaved surfaces demonstrates that the microscopic electronic structures of YbInCu4 observed with infrared spectroscopy indeed undergo a sudden change upon the valence transition. The gradual temperature-evolution of Rp(w) is most likely due to the compositional and/or Yb-In site disorders caused by polishing.

4 pages, 4 figures, Fig.1(a) corrected

References in corpus (5)

• Slow crossover in YbXCu4 intermediate valence compounds
• Pseudogap Formation and Heavy Carrier Dynamics in Intermediate Valence YbAl3
• Kondo Scaling in the Optical Response of YbIn_(1-x)Ag_xCu_4
• Optical study of the electronic phase transition of strongly correlated YbInCu_4
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• Kondo lattice excitation observed using resonant inelastic X-ray scattering at the Yb $M_5$ edge