On the origin of the Fermi arc phenomenon in the underdoped cuprates: signature of KT-type superconducting transition.

The origin of the Fermi arc phenomenon in the pseudogap phase of the underdoped cuprates is studied in the thermal phase fluctuation scenario. An XY-type lattice model with a built in d-wave structure is introduced to describe the phase fluctuation effect in the cuprates. A sharp ridge-like structure in the spectral function A(k, ω = 0) is found to emerge abruptly above the Kosterlitz-Thouless (KT) transition temperature (T(KT)) on the underlying Fermi surface. This ridge-like structure in A(k, ω = 0) bears a close resemblance to the observed Fermi arc phenomenon in its temperature dependence and shape in the momentum space. These results provide yet more strong evidence for the KT transition nature of the superconducting transition in the underdoped cuprates.