English

Superconductivity induced by Mg deficiency in non-centrosymmetric phosphide Mg$_2$Rh$_3$P

Superconductivity 2019-12-30 v1

Abstract

The search for non-centrosymmetric superconductors that may exhibit unusual physical properties and unconventional superconductivity has yielded the synthesis of a non-centrosymmetric phosphide Mg2_2Rh3_3P with an Al2_2Mo3_3C-type structure. Although stoichiometric Mg2_2Rh3_3P does not exhibit superconductivity at temperatures above 2 K, we found that an Mg deficiency of approximately 5 at.% in the Mg2_2Rh3_3P induced superconductivity at 3.9 K. Physical properties such as the lattice parameter a = 0.70881 nm, Sommerfeld constant γn\gamma_n = 5.36 mJ mol1^{-1} K2^{-2}, specific heat jump Δ\DeltaCel_{el}/γn\gamma_nTc = 0.72, electron-phonon coupling constant λ\lambdaep_{e-p} = 0.58, upper critical field Hc2_{c2}(0) = 24.3 kOe, and pressure effect dTc/dP = -0.34 K/GPa were measured for the superconducting Mg2δ_{2-\delta}Rh3_3P (δ\delta \sim 0.1). Band-structure calculations indicate that exotic fermions, which are not present in high-energy physics, exist in Mg2_2Rh3_3P. Since Mg, Rh, and P are the first elements used at each crystal site of Al2_2Mo3_3C-type compounds, the discovery of Mg2_2Rh3_3P may guide the search for new related materials.

Keywords

Cite

@article{arxiv.1910.06523,
  title  = {Superconductivity induced by Mg deficiency in non-centrosymmetric phosphide Mg$_2$Rh$_3$P},
  author = {Akira Iyo and Izumi Hase and Hiroshi Fujihisa and Yoshito Gotoh and Nao Takeshita and Shigeyuki Ishida and Hiroki Ninomiya and Yoshiyuki Yoshida and Hiroshi Eisaki and Kenji Kawashima},
  journal= {arXiv preprint arXiv:1910.06523},
  year   = {2019}
}

Comments

12 pages, 9 figures. arXiv admin note: text overlap with arXiv:1603.03093 by other authors