Mapping the Pseudogap by Fourier Transform Scanning Tunneling Spectroscopy in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$

The relationship between pseudogap and superconductivity in cuprate superconductors remains an important open question. To shed light on this issue, we have used Fourier-transform scanning tunneling microscopy to map quasiparticle interference (QPI) patterns as well as the ``checkerboard,'' a weak charge modulation associated with the pseudogap, as a function of doping and temperature in Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ (Bi-2212). We can extract the doping dependence of the pseudogap transition temperature T* within the superconducting dome. Our results strongly suggest that the pseudogap is a competing order.