Coexistence of superconductivity and a charge density wave in LaPt₂(Si_1−xGe_x)₂(0 ⩽ x ⩽ 0.5)

Abstract

Interplay between a charge density wave (CDW) and superconductivity in LaPt2(Si1-x Ge x )2 has been studied by electrical transport and magnetic measurements. LaPt2Si2 crystallizes in CaBe2Ge2 type structure which shows a first order structural phase transition from tetragonal to orthorhombic accompanied by a CDW transition at 112 K and superconducting transition at around 1.22 K as confirmed by temperature dependence of resistivity and magnetic measurements. For 2[Formula: see text] doping of germanium, while the CDW temperature T CDW decreases, the superconducting transition temperature T C shows an increase. T CDW increases for 5[Formula: see text] doping of germanium and the superconducting transition decreases. These findings demonstrate the competing nature of a CDW and superconductivity.

Multigap superconductivity in the charge density wave superconductor LaPt2Si2

“…Furthermore, theoretical prediction of coexistence of CDW and superconductivity in LaPt 2 Si 2 by Kim et al 41 has been confirmed experimentally in our earlier reports. 15,16 On the other hand, electronic structure calculation predicts quasi-two-dimensional nature of the Fermi surface 42 similar to that seen for iron pnictides. These observations conjointly hint towards an exotic origin of superconductivity in the system.…”

“…38,39 In this framework, LaPt 2 Si 2 turns out to be quite an interesting system hosting diverse exciting phenomena such as lack of inversion symmetry in crystal structure, CDW transition, structural phase transition from tetragonal to orthorhombic structure and superconductivity. 13,15,16,40 Through small angle electron diffration study, 13 CDW wave vector has been confirmed to be (n/3, 0, 0), where n (= 1, 2) is the order of reflection, which requires tripling of unit cell be-low T CDW . Furthermore, theoretical prediction of coexistence of CDW and superconductivity in LaPt 2 Si 2 by Kim et al 41 has been confirmed experimentally in our earlier reports.…”

“…[11][12][13][14] A new class of intermetallic series, RPt 2 Si 2 (R=La, Pr) has been intensively investigated recently which exhibits strong interplay between CDW and superconductivity. 13,[15][16][17][18] RPt 2 Si 2 crystalizes in primitive tetragonal CaBe 2 Ge 2 type structure (space group P 4/nmm) 13,15,16 having a close resemblance to the ThCr 2 Si 2 type structure found in pnictide and heavy fermion SC. However, one striking difference between these two structures accounts the fact that the former one lacks inversion symmetry in the crystal structure which contains two inequivalent [Ge1-Be2-Ge1] and [Ge2-Be1-Ge2] layers with Ca atom (or R atom for RPt 2 Si 2 ) being sandwiched between them.…”

“…The detail procedure of sample preparation can be found in Ref. 15 The detail of sample characterization has been provided in Supplemental Material. 44 The µSR experiments were performed in MUSR spectrometer at ISIS pulsed muon facility of the Rutherford Appleton Laboratory, United Kingdom.…”

Isotropic s -wave superconductivity in the noncentrosymmetric charge density wave superconductor SrPt2As2

“…Recently, in the quest to discover new CDW superconductors, a few nonmagnetic 122-type Pt-based arsenides, isostructural to 122 Fe-based arsenides, were studied in order to explore the coexistence phenomena of SC and CDW [30][31][32][33][34][35][36][37]. Among them, SrPt 2 As 2 has received significant attention because of the possible coexistence of CDW and SC with T c ≈ 5 K, the latter being relatively higher than that of other Pt-based arsenides [38].…”