The electron tunneling spectroscopy is performed on Pb-I-La1-xSrxCuO4 (LSCO) junctions fabricated on high quality LSCO single crystals grown by traveling solvent floating zone (TSFZ) method. For the junctions fabricated parallel to ab-planes, periodic sharp spikes in the spectrum are observed at ∼ 6 × (2n + 1) mV, where n is a natural number, while for the junctions fabricated on the (001) plane only gap structures corresponding to Pb and LSCO are observed. We ascribe the spike structure to subbands in the electron density of states caused by the Andreev reflections on the periodically modulated gap potential along the c-axis of LSCO.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering