Superconductivity in MBE grown InN

Abstract

We present the experimental investigation of superconductivity in unintentionally doped MBE grown InN samples with various InN film thicknesses. A significant change in resistivity was observed at 3.82K, for an 1080 nm InN layer with carrier concentration n(3D) = 1.185x10(19) cm(-3). However, no significant resistance change was observed in the case of InN samples with carrier density of 1.024x10(19) cm(-3), 1.38x10(19) cm(-3), and thicknesses of 2070 and 4700 nm, respectively. The carrier density of all investigated samples was within the range of values between the Mott transition (2x10(17) cm(-3)) and the superconductivity to metal transition (7x10(20) cm-(3)). We believe that at lower temperatures (He-3) which we cannot achieve with our set-up, the phase transition in other samples is likely to be observed. The origin of the observed anisotropic type-II superconductivity is discussed