Recently, complex rotational symmetry-breaking phenomena have been discovered experimentally in cuprate superconductors. To find the realized order parameters, we study various unconventional charge susceptibilities in an unbiased way by applying the functional-renormalization-group method to the d−p Hubbard model. Without assuming the wave vector of the order parameter, we reveal that the most dominant instability is the uniform (q=0) charge modulation on the px and py orbitals, which possesses d symmetry. This uniform nematic order triggers another nematic p-orbital density wave along the axial (Cu-Cu) direction at Qa≈(π/2,0). It is predicted that uniform nematic order is driven by the spin fluctuations in the pseudogap region, and another nematic density-wave order at q=Qa is triggered by the uniform order. The predicted multistage nematic transitions are caused by Aslamazov–Larkin-type fluctuation-exchange processes.
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