Mekonnen, Sintayehu2018-07-032023-11-092018-07-032023-11-092010-07http://10.90.10.223:4000/handle/123456789/5706The recent discovery of superconductivity at moderately high temperature(26K to 55K) in doped iron-based pnictides(RnO1􀀀xFxFeAs),where Rn=La,Ce,Sm,Pr,Nd.etc) having layered-structure like cuprates,has triggered challenge towards understanding the paring mechanism. In this work we analyze superconductivity and the Jahn Teller e ect in this newly discovered La(O1􀀀xFx)FeAs superconductor. after reviewing the current nding on this systems, we suggested in phonon-mediated and distortion- eld-mediated paring processes give the right order of superconducting critical temperature Tc.The distortion- eld modes arise from Jahn-Teller e ects due to degenerate or near-degenerate iron 3dxz and 3dyz orbitals. The interaction of these degenerate electrons with phonon and distortion eld results change of shape of orbitals consequentially a change in splitting of electronic orbitals. Ac- cording to our calculated result in chapter three that superconducting parameters;energy gap ( ) no of particles inside Fermi surface(N(0)),coe cient of isotopic constant ( ) are a ected due to Jahn-Teller distortion,consequently superconducting transition tempera- ture (Tc) is a ected . The calculated parameters are coincide with experimental values for suitable values of constantsenJahn Teller Effect in LA(O1􀀀XFX)Feas SuperconductorThesis