Thermal conductivity across a twin boundary in d-wave superconductor

摘要

We consider excitation spectrum near a twin boundary in an orthorhombic $d+s$superconductor. The low-energy spectrum is highly sensitive to the presence ofthe small amount of s-wave component. Robustness of the bound states at theFermi level with respect to impurities and an extra boundary potential isinvestigated. The role of Andreev transmission process for the low-temperaturethermal conductivity across twin boundaries is studied for an impuresuperconductors. At very low temperatures the bulk part and the twin boundariespart of the thermal conductivity have similar linear-$T$ dependences, whereasat intermediate temperatures the two contributions behave like $T^3$ and $T^2$,respectively.