Anisotropic superconductivity of InN grown by molecular beam epitaxy on sapphire (0001)

We report a study of anisotropic superconductivity of InN grown by MBE on a sapphire (0001) surface. InN shows a resistivity anomaly below 3.5 K and a superconductivity below 1.5 K. The superconductivity is of the second kind and its H-c1 and H-c2 are 0.08 and 0.8 T, respectively, when the magnetic field (B) is applied parallel to the c-axis. When B perpendicular to c-axis , H-c1 and H-c2 are 0.23 and 2.3 T, respectively, InN demonstrates negative magnetoresistance above H-c2 and the resistivity decreases 4% at 12 T unde r the B parallel to c-axis configuration. These results indicate that the s uperconductivity of InN is anisotropic.