ab-Plane surface impedance of the single-layer cuprate Tl2Ba2CuO6+δ

Abstract The ab -plane surface impedance of Tl 2 Ba 2 CuO 6+δ (Tl-2201) has been measured at 14.4, 24.8 and 35.9 GHz using cavity perturbation techniques. The result of these measurements is a picture of the superconducting electrodynamics of Tl-2201 that closely resembles those of YBa 2 Cu 3 O 7−δ and Bi 2 Sr 2 CaCu 2 O 8 . Here we describe the main features of our measurements; in particular, we see a linear temperature dependence of the in-plane penetration depth at low temperature, consistent with an unconventional pairing state with line nodes. The simple crystal structure of Tl-2201 (tetragonal, with a single CuO 2 plane/unit cell) makes this an interesting addition to our knowledge of cuprate electrodynamics.