  We investigate a two-component atomic Fermi gas with population imbalance in
the presence of Rashba-type spin-orbit coupling (SOC). As a competition between
SOC and population imbalance, the finite-temperature phase diagram reveals a
large varieties of new features, including the expanding of the superfluid
state regime and the shrinking of both the phase separation and the normal
regimes. For sufficiently strong SOC, the phase separation region disappears,
giving way to the superfluid state. We find that the tricritical point moves
toward regime of low temperature, high magnetic field, and high polarization as
the SOC increases.
