Specific heat measurements in clean FeSe single crystals

抄録

The pairing symmetry of superconducting gap is a key to understand the mechanism of superconductivity. Measuring specific heat is a useful technique to obtain the gap structure of bulk sample, comparing with ARPES and STM, which are limited to the surface of sample. The sample I use in the specific heat experiments is a single crystalline FeSe which has the simplest crystal structure in iron-based superconductors with high quality (Tc ~9 K and a sharp specific heat jump). Some published materials mentioned FeSe has line nodes while others support that FeSe is nodeless with multiple gaps. In order to get some insight into this issue, I perform specific heat measurements at low temperatures (H//c) and angle-resolved specific heat (ARSH) at different temperatures and field (H//ab), respectively.