  The experimental determination of the superconducting transition requires the
observation of the emergence of zero-resistance and perfect diamagnetism state.
Based on the close relationship between superconducting transition temperature
(Tc) and electron density of states (DOS), we take two typical superconducting
materials Hg and ZrTe3 as samples and calculate their DOS versus temperature
under different pressures by using the first-principle molecular dynamics
simulations. According to the analysis of the calculation results, the main
contributors that induce superconducting transitions are deduced by tracing the
variation of partial density of states near Tc. In particular, the microscopic
mechanism of pressure increasing Tc is further analyzed.
