In the Van Hove scenario including orthorhombic distortion effect, we develop a pair of coupled gap equations for the mixed (sϩid)-wave order parameter. It is found that a mixed sϩid symmetry state is realized in a certain range of relative strength of the s and d interactions, and there are two second-order transitions between the mixed and the pure symmetry states. Particular attention is paid to the temperature dependence of two components in the mixed order parameter as well as their evolution from a pure s to a pure d symmetry state.

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