In explicit CP violation scenario of the minimal non-minimal supersymmetric standard model (MNMSSM), the possibility of a strongly first-order electroweak phase transition (EWPT) is investigated at the one-loop level, where the radiative corrections
from the loops of the top and stop quarks are taken into account. Assuming that the stop quark masses are not degenerate, the radiative corrections due to the stop quarks give rise to a CP phase, which triggers the scalar-pseudoscalar mixing in the Higgs sector of the MNMSSM. The lighter stop quark need not always to have a small mass in order to ensure the strongly first-order EWPT. In the MNMSSM with explicit CP violation, it is found that the strength of the first-order EWPT depends on several factors, such as the lightest neutral Higgs boson mass and the nontrivial CP phase arising from stop quark masses. The effects of these factors are discussed.
