Inhaltszusammenfassung

High-resolution photoemission measurements using synchrotron radiation are presented for the body-centered-tetragonal superconducting pseudoternary system Y(Rh1-xRux)4B4 covering the range of composition 0.10?x?0.90. The superconducting phase diagram determined down to 4 mK reproduces the sharp drop in the superconducting critical temperature Tc for x>xcr=0.35, which is characteristic for this class of compound. No superconductivity was observed for the sample with x=0.70, whereas the sample ...High-resolution photoemission measurements using synchrotron radiation are presented for the body-centered-tetragonal superconducting pseudoternary system Y(Rh1-xRux)4B4 covering the range of composition 0.10?x?0.90. The superconducting phase diagram determined down to 4 mK reproduces the sharp drop in the superconducting critical temperature Tc for x>xcr=0.35, which is characteristic for this class of compound. No superconductivity was observed for the sample with x=0.70, whereas the sample with x=0.90 became superconducting again at Tc=140 mK. From a comparison between the valence-band spectra near the Fermi level EF and band-structure calculations by Jarlborg et al. for the related compounds MRh4B4 with M=Y, Gd, Ho, Er, and Lu, we conclude that a shift of EF to lower energies with increasing x is the underlying mechanism for the Tc(x) behavior. In our previous study on Ho(Rh1-xRux)4B4, for which supplementary data are also presented, the same features were observed. Our measurements indicate that hybridization effects upon alloying Ru for Rh cannot explain the observed behavior of Tc. » weiterlesen» einklappen

Autoren

Klassifikation

DFG Fachgebiet:
Physik der kondensierten Materie

DDC Sachgruppe:
Physik