Abstract
The pressure effect on the newly discovered charge-transferred -based superconductor, , with a of 1.5 K at ambient pressure, is investigated by transport and magnetic measurements. Accompanied with the enhancement of metallicity under pressures, the onset superconducting transition temperature increases abruptly around 1.0 GPa, reaching K at 2.26 GPa. Alternating current magnetic susceptibility measurements indicate that a new superconducting phase with a higher emerges and dominates at high pressures. In the broad pressure window of GPa, the high- phase coexists with the low- phase. Hall effect measurements reveal a significant difference in electronic structures between the two superconducting phases. Our work devotes the effort to establish the commonality of pressure effect on the -based superconductors, and also uncovers the importance of electron carrier density in the high- phase.
- Received 2 November 2014
- Revised 3 December 2014
DOI:https://doi.org/10.1103/PhysRevB.90.220510
©2014 American Physical Society