Topological superconductivity (TSC) is a highly sought-after superconducting
state hosting topological order and Majorana excitations. In this work, we
explore the mechanism to the TSC in the doped Mott insulators with
time-reversal symmetry (TRS). Through large-scale density matrix
renormalization group study of an extended triangular-lattice t-J model on
the 6- and 8-leg cylinders, we identify a d+id-wave chiral TSC phase with
spontaneous TRS breaking, which is characterized by a Chern number C=2 and
quasi-long-range superconducting order. We map out the quantum phase diagram
with tuning the next-nearest-neighbor (NNN) electron hopping and spin
interaction. In the weaker NNN-coupling regime, a charge stripe phase
coexisting with strong spin fluctuations and fluctuating superconductivity is
revealed. The TSC emerges in the intermediate-coupling regime, which has a
transition to a d-wave superconducting phase at larger NNN couplings. The
emergence of the TSC is driven by geometrical frustrations and hole dynamics,
which suppress spin correlation and charge order, leading to a topological
quantum phase transition.Comment: 6+10 pages, 5+9 figue