Detecting the minimum gap locus in ARPES spectra of Bi2201*

Recent angle-resolved photoemission (ARPES) studies have reported a direct evidence for the competing nature of the pseudogap by showing that the pseudogap dispersion is not tied to Fermi momentum ($k_{F}$)[1,2]. In this study, to get more detailed information on how the competing pseudogap evolves across the pseudogap temperature (T*), we introduce a new analysis method for spectral weight. We found a clear indication that the pseudogap opens at T* with the minimum gap locus deviating from $k_{F}$, which is completely different manner from the gap opening by simple superconductivity, and strongly supports that the pseudogap is another distinct order. [1] M. Hashimoto and R.-H. He {\it et~al.}, Nature Phys. {\bf 6}, 14-418 (2010). [2] R.-H. He and M. Hashimoto {\it et~al.}, Science {\bf 331}, 1579-1583 (2011).