SrPt2As2 single crystals with CaBe2Ge2-type structure were synthesized by self-melting technique. X-ray diffraction, transmission electron microscopy, electrical resistivity, specific heat and optical spectroscopy measurements were conducted to elucidate the properties of SrPt2As2. SrPt2As2 single crystals exhibit a superconducting transition at 5.2K, experiencing a structural phase transition well above room temperature (about 455K). The superconducting and structural phase transition temperatures are both reduced by 6% Iridium doping. Both pure SrPt2As2 and the doped single crystals are revealed to be highly metallic with rather high plasma frequencies. In particular, the optical spectroscopy measurement revealed two gap-like suppression features. We elaborated that the one at higher energy scale could be ascribed to the correlation effect, while the other one at lower energy scale is related to the structural phase transition, leading to the removal of a small portion of the Fermi surfaces.
@article{arxiv.1204.5984,
title = {Single crystal growth and optical conductivity of SrPt$_2$As$_2$ superconductors},
author = {A. F. Fang and T. Dong and H. P. Wang and Z. G. Chen and B. Cheng and Y. G. Shi and P. Zheng and G. Xu and L. Wang and J. Q. Li and N. L. Wang},
journal= {arXiv preprint arXiv:1204.5984},
year = {2013}
}