Abstract
Low-temperature specific heat has been measured in FeS superconductor with the transition temperature of 4.55 K. It is found that the low-temperature electronic specific heat Ce/T can be fitted to a linear relation in the low-temperature region, but fails to be described by an exponential relation as expected by an s-wave gap. We try fittings to the data with different gap structures and find that a model with one or two nodal gaps can fit the data. Under a magnetic field, the field induced specific heat coefficient Δγe=[Ce(H)-Ce(0)]/T shows the Volovik relation Δγe(H) H, suggesting the presence of nodal gap(s) in this material.
| Original language | English |
|---|---|
| Article number | 104520 |
| Journal | Physical Review B |
| Volume | 93 |
| Issue number | 10 |
| DOIs | |
| State | Published - Mar 17 2016 |
| Externally published | Yes |
Funding
ACKNOWLEDGMENTS We appreciate the discussions with S. Y. Li. This work is supported by the NSF of China, the Ministry of Science and Technology of China (973 projects: 2011CBA00102, 2012CB821403, 2010CB923002), and PAPD.