Two-dimensional behavior of the naturally layered superconductor (LaSe)1.14(NbSe2)
Abstract The three-dimensional to two-dimensional (2D) crossover of the superconducting state is presented for the naturally layered single crystal of (LaSe) 1.14 (NbSe 2 ) with the critical temperature T c of 1.23 K. Namely, the temperature dependence of the upper critical magnetic field B c2 parallel to the layers reveals an upturn at the crossover temperature T * due to the vortex confinement between the superconducting layers. Below this temperature in the 2D regime the angular dependence of B c2 displays a cusp at the field parallel to the layers. In the superconducting state the interlayer transport is accomplished in this system by the tunneling of quasiparticles and Cooper pairs.