Single top quark production cross section at LHC in ATLAS

Measurements of the single top quark production cross sections in proton proton collisions with the ATLAS detector at the Large Hadron Collider are presented. Measurements of single top quark production in the t- and Wt-channels are shown and the determination of the CKM matrix element |Vtb| is discussed. We also discuss the separate measurement of the top and anti-top quark cross section and the ratio. These measurements are sensitive to the parton distribution function in the proton. In addition, the results of a search for flavor changing neutral currents in the single top production is presented.