arXiv subjects

L. Q. Che

Publications and source records attributed to L. Q. Che.

3 recordsLinked to original sources

arXiv2021

Nodeless superconductivity in the charge density wave superconductor LaPt$_2$Si$_2$

We have studied the superconducting gap structure of LaPt$_2$Si$_2$ by measuring the temperature dependence of the London penetration depth shift $Δλ(T)$ and point contact spectroscopy of single crystals. $Δλ(T)$ shows an exponential temperature dependence at low temperatures, and the derived normalized superfluid density $ρ_{s}(T)$ can be well described by a single-gap s-wave model. The point-contact conductance spectra can also be well fitted by an s-wave Blonder-Tinkham-Klapwijk model, where the gap value shows a typical BCS temperature and magnetic field dependence consistent with type-II superconductivity. These results suggest fully gapped superconductivity in LaPt$_2$Si$_2$, with moderately strong electron-phonon coupling.

cond-mat.supr-con↗

arXiv2016

Synthesis, characterization and physical properties of layered bismuthide PtBi$_2$

We report details of single crystal growth of stoichiometric bismuthide PtBi$_2$ whose structure consists of alternate stacking of Pt layer sandwiched by Bi bilayer along the $c$-axis. The compound crystallizes in space group P-3 with a hexagonal unit cell of $a$=$b$=6.553$Å$, $c$=6.165$Å$. The magnetization data show opposite sign for fields parallel and perpendicular to the Pt layers, respectively. The $T$-dependent resistivity is typical of a metal and the magnetic response shows clear two types of charge carriers and the validity of the semi-classical Kohler's rule. Its physical properties was discussed in comparison with recently proposed topological superconductor $β$-PdBi$_2$.

cond-mat.str-el↗

arXiv2015

Nodeless superconductivity in noncentrosymmetric PbTaSe$_2$ single crystals

We report an investigation of the superconducting order parameter of the noncentrosymmetric compound PbTaSe$_2$, which is believed to have a topologically nontrivial band structure. Precise measurements of the London penetration depth $Δλ(T)$ obtained using a tunnel diode oscillator (TDO) based method show an exponential temperature dependence at $T\ll T_c$, suggesting a nodeless superconducting gap structure. A single band s-wave model well describes the corresponding normalized superfluid density, with a gap magnitude of $Δ(0)=1.85T_c$. This is very close to the value of $1.76T_c$ for weak-coupling BCS superconductors, indicating conventional fully-gapped superconductivity in PbTaSe$_2$.

cond-mat.supr-con↗