Magnetic field dependence of the density of states in the multiband superconductor b-Bi2Pd

E. HERRERA; I. GUILLAMÓN; J. A. GALVIS; A. CORREA; A. FENTE; R. F. LUCCAS; F. MOMPEAN; M. GARCÍA-HERNÁNDEZ; S. VIEIRA; J. P. BRISON; H. SUDEROW

Physical Review B

AMER PHYSICAL SOC

Lugar: New York; Año: 2015 vol. 92 p. 54507 - 54507

We present very low temperature scanning tunneling microscopy (STM) experiments on single crystalline samples of the superconductor b-Bi2Pd. We find a single fully isotropic superconducting gap. However, the magnetic field dependence of the intervortex density of states is higher than the one expected in a single gap superconductor, and the hexagonal vortex lattice is locked to the square atomic lattice. Such increase in the intervortex density of states and vortex lattice locking have been found in superconductors with multiple superconducting gaps and anisotropic Fermi surfaces. We compare the upper critical field Hc2(T) obtained in our sample with previous measurements and explain available data within multiband supercondutivity. We propose that b-Bi2Pd is a single gap multiband superconductor. We anticipate that single gap multiband superconductivity can occur in other compounds with complex Fermi surfaces.