Soft-mode enhanced type-I superconductivity in LiPd2Ge
- Gdansk University of Technology (Poland); OSTI
- AGH University of Science and Technology, Kraków (Poland)
- Princeton Univ., NJ (United States)
- Gdansk University of Technology (Poland)
The synthesis, crystal structure, and physical properties (magnetization, resistivity, heat capacity) in combination with theoretical calculations of the electronic structure and phonon properties are reported for intermetallic compounds LiPd2X (X = Si, Ge, and Sn). LeBail refinement of powder x-ray diffraction data confirms that all compounds belong to the Heusler family (space group $$\textit{F m-3m}$$, No. 225). The lattice parameter increases with atomic size of X, and its value varies from $$\textit{a}$$ = 5.9059(4) Å for LiPd2Si and $$\textit{a}$$ = 6.0082(3)Å for LiPd2Ge, to $$\textit{a}$$ = 6.2644(1) Å for LiPd2Sn. The first compound, LiPd2Si, has apparently not been previously reported. All measured quantities demonstrate that LiPd2Ge exhibits superconductivity below $$T_c$$ = 1.96 K and the normal- and superconducting-state data indicate that it is a weak-strength type-I superconductor ($$C/γT_c$$ = 1.38) with electron-phonon coupling constant $$λ_{e–p}$$ = (0.53–0.56). LiPd2Si and LiPd2Sn are not superconducting above 1.68 K. The experimental observations are supported by theoretical calculations which show that LiPd2Ge has the highest computed $$λ_{e–p}$$ and $$T_c$$ of the group. A strong softening of the acoustic phonon mode is calculated, and in the case of X = Ge and Sn, imaginary phonon frequencies were computed. In this work, the soft mode is most pronounced in the case of LiPd2Ge, which suggests its correlation with superconductivity.
- Research Organization:
- Princeton Univ., NJ (United States)
- Sponsoring Organization:
- National Science Centre of Poland (NCN); USDOE Office of Science (SC), Basic Energy Sciences (BES)
- Grant/Contract Number:
- FG02-98ER45706
- OSTI ID:
- 1800955
- Journal Information:
- Physical Review B, Journal Name: Physical Review B Journal Issue: 2 Vol. 102; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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