Evidence for nodal quasiparticles in the nonmagnetic superconductor YNi2B2C via field-angle-dependent heat capacity.
Field-angle dependent heat capacity of the nonmagnetic borocarbide superconductor YNi2B2C reveals a clear fourfold oscillation, the first observation of its kind. The observed angular variations were analyzed as a function of magnetic field angle, field-intensity, and temperature to provide its origin. The quantitative agreement between experiment and theory strongly suggests that we are directly observing nodal quasiparticles generated along <100> by the Doppler effect. The results demonstrate that field-angle heat capacity can be a powerful tool in probing the momentum-space gap structure in unconventional superconductors such as high T(c) cuprates, heavy-fermion superconductors, etc.
Park
Tuson
T
Department of Physics and Material Research Laboratory, University of Illinois at Urbana-Champaign, Illinois 61801, USA.
Salamon
M B
MB
Choi
Eun Mi
EM
Kim
Heon Jung
HJ
Lee
Sung-Ik
SI