Thermal excitations in (d + s)-wave superconductors

We investigate the properties of weakly coupled clean orthorhombic supercon ductors with d + s pairing symmetry. The temperature dependence of the quas iparticle specific heat C-B(T), the spin susceptibility chi(B)(T), and the quasiparticle contribution K-B(T) to the electronic supercurrent response ( magnetic field penetration depth) is studied. In the limit T --> 0 we discu ss analytically the structure of the temperature pourer laws as influenced by lattice orthorhombicity and a finite s-wave contribution to the pairing interaction. (C) 2000 Elsevier Science B.V. All rights reserved.