  We study holographic superconductor model with two scalar fields coupled to
one single Maxwell field in the AdS soliton background away from the probe
limit. We disclose properties of phase transitions mostly from the holographic
topological entanglement entropy approach. With different sets of parameters,
we observe various types of transitions, especially a new first order phase
transition between the condensation of different order parameters in the
insulator/superconductor system. Our results show that the entanglement entropy
is a good probe to critical phase transition points and the order of phase
transitions in the two-order model. We also conclude that the entanglement
entropy is useful to some extent in determining the physically supported
phases. In addition, we investigate properties of the condensation through the
scalar operator and the charge density in the dual theory. As a summary, we
draw the complete phase diagram of the effects of the scalar charge on phase
transitions. At last, we give some qualitative understanding and obtain the
analytical condition for the first order phase transition to occur.
