Superconductivity and Charge Density Waves in the Two-Dimensional material BSTS

The interplay between two quantum phenomena, charge density waves (CDWs) and superconductivity in low-dimensional materials leads to a complex relationship of competition and coexistence, offering a promising avenue for discovering new superconductors. In this study, we investigate the structural and electronic properties of BaSbTe₂S (BSTS), a newly identified two-dimensional chalcogenide that hosts CDW order at ambient conditions. Through four-probe electrical resistivity measurements, AC magnetic susceptibility measurements and x-ray diffraction structural analysis, we observe the suppression of CDW order with increasing pressure, coinciding with the emergence of superconductivity at a critical pressure threshold. Our results reveal a pressure-dependent superconducting phase with a maximum critical temperature (Tc) of 7.5 K at 13.6 GPa. Furthermore, we identify a semiconductor-to-metal transition preceding the onset of superconductivity. These findings highlight BSTS as a compelling platform for exploring quantum phase competition and provide further evidence of the intricate dance between CDW order and superconductivity in low-dimensional materials.