Electronic structures and superconductivity in LuTE2Si2 phases (TE= d-electron transition metal)

Superconductivity in single crystalline LuPd2Si2 probed by heat capacity measurements

“…The analysis of the collected x-ray powder diffraction pattern (see figure 1(b)) confirmed the tetragonal ThCr 2 Si 2 -type crystal structure of the studied compound and proved the single-phase character of the specimens studied. While the refined lattice parameters a=4.0838(3)Åand c=9.8729(2)Åare consistent with the previously reported ones [8,13,14], the derived atomic coordinate z Si =0.3802(5) differs slightly from that obtained for the polycrystalline sample (0.3866 (11)) [8]. Moreover, the crystals were found to be homogeneous, with the experimentally determined composition of Lu/Pd/Si=19.9/38.9/ 41.2 at.% being very close to the expected stoichiometry.…”

“…in μ 0 H=25mT, which was sufficient to suppress the superconductivity for both directions of applied field) was used to estimate the Sommerfeld coefficient γ n and the phononic , where n is the number of atoms per formula unit and R is the universal gas constant. In this way we found that Θ D in LuPd 2 Si 2 is of about 327K, which is similar to the values of Θ D obtained for polycrystalline samples of isostructural LuT 2 Si 2 systems [8].…”

“…one can calculate the bare density of states at the Fermi level to be here with two values of the Sommerfeld coefficient: the experimental one (γ n =7.0mJK −2 mol −1 ) given above and the calculated (γ b =5.29mJK −2 mol −1 ) from first principles value from our previous study [8]. In such a way, one gets an even lower value of l = -0.32 el ph * .…”

“…Motivated by those discoveries, we have recently performed a systematic re-investigation of non-magnetic 1:2:2 silicides and germanides, which have resulted in several reports on properties of the whole series of compounds [4][5][6][7][8], as well as more detailed studies of selected superconductors both on polycrystalline samples [9,10] and single crystals [11,12], confirming or discovering the presence of superconductivity in several compounds.…”

First Principles Calculations of Superconducting Critical Temperature of ThCr$_2$Si$_2$-Type Structure

“…Moreover, from the calculated Fermi surface (Fig. 8), we found that both of compounds adopted the tetragonal ThCr2Si2-type structure having three-dimentional electron-like and hole-like multiband FS's as most of the same type compounds have 45,46 . Finally, the two compounds appear to be typical of superconductors mediated by phonons (BSC-type superconductor) exhibing a superconductivity at low temperature (however, it is high compared to another compounds having the same structure) and it is not required any special dimensionality of Fermi surface requiring possible nesting vector which can favor electron's pairscoming from different conduction band 47 .…”