Temperature and magnetic field dependent tunneling spectroscopy of PtIr/Sr${}_{0.9}$La${}_{0.1}$CuO${}_2$ point contact

Low barrier quasiparticle tunneling spectroscopy on Sr${}_{0.9}$La${}_{0.1}$CuO${}_2$ has been studied with PtIr/Sr${}_{0.9}$La${}_{0.1}$CuO${}_2$ point contacts at various temperatures and magnetic fields. No zero-bias conductance peaks are observed. By fitting tunneling conductance to Blonder-Tinkham-Klapwijk theory, the temperature dependent s-wave superconducting gaps are obtained. The present results exclude the possibility of d-wave symmetry for the pair gap in Sr${}_{0.9}$La${}_{0.1}$CuO${}_2$, and do not support the conventional phonon mediated pairing in this system either.