New superconductor SrPt2Ge2 with T-c=10.2 K

作者：Ku H C^*; Chen I A; Huang C H; Chen C W; You Y B; Tai M F; Hsu Y Y

来源：Physica C-Superconductivity and Its Applications, 2013, 493: 93-95.

DOI：10.1016/j.physc.2013.03.036

• New superconductors
• 122-bct layer crystal structure
• Germanide

Contrast to superconducting compounds SrNi2Ge2 (T-c = 1.1 K) and SrPd2Ge2 (T-c = 3.2 K) with the BaFe2-As-2-type body-center-tetragonal (122-bct) layer structure (space group I4/mmm), SrPt2Ge2 crystallized in a pseudo-tetragonal, monoclinic structure with space group P2(1) and lattice parameters a = 0.4401(4) nm %26lt; b = 0.4435(4) nm, c = 0.9764(10) nm and beta = 90.5 degrees %26gt; 90 degrees. Superconductivity with T-c = 10.2 K was observed in this new compound. However, a weak diamagnetic shielding signal of -3.2 x 10 (2) cm(3)/mol at 2 K indicates that superconductivity is not from the bulk monoclinic phase but from a minor metastable 122-bct high-temperature phase with a similar to 0.44 nm, c similar to 0.98 nm, beta = 90 degrees. This is the highest T-c reported outside the iron-based layer compounds with the 122-bct structure. High-T-c superconductivity is due to strong quasi-2D Pt-Ge-Pt 5d(xz,yz)-4p-5d(xz,yz) hybridization in the Pt-Ge layer with squeezed PtGe4 tetrahedral crystal field and Pt-5d(8) spin-orbital interaction in the metastable 122-bct phase and is another example of multi-band (d(xz)/d(yz)/d(xy)) non-conventional s-wave superconductor.

• 出版日期2013-10
• 单位清华大学