Structure and Transport in ultrathin SrRuO$_{3}$

SrRuO$_{3}$ (SRO) is a common electrode material in oxide thin film growth, and is also representative ``bad'' metal. Although bulk SRO is orthorhombic, a typical study grows a pseudocubic film on SrTiO$_{3}$(100) substrate. We have measured electrical conductivity and structure of in-situ grown SRO films using scanning probe microscopy, low energy electron diffraction (LEED) and scanning transition electron microscopy. The films remain conducting down to the thickness of one layer. LEED displayed sharp (1x1) patterns at 80 and 300K up to 5 layers, but revealed strong half-order spots with weak intensity at quarter-order by 20 layers. STM images show the surfaces of thick films to have many vacancies, which first principles theory suggests are missing SrO molecules.