Heon Jung Kim

Evidence for Nodal Quasiparticles in the Nonmagnetic Superconductor YNi2B2C via Field-Angle-Dependent Heat Capacity

Field-angle dependent heat capacity of the non-magnetic 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 Tc cuprates, heavy fermion superconductors, etc.

Evidence for the coexistence of an anisotropic superconducting gap and nonlocal effects in the nonmagnetic superconductor LuNi2B2C.

A study of the dependence of the heat capacity C(p)(alpha) on the field angle in LuNi2B2C reveals an anomalous disorder effect. For pure samples, C(p)(alpha) exhibits a fourfold variation as the field H (alpha=0). A slightly disordered sample, however, develops anomalous secondary minima along <110> for mu(0)H>1 T, leading to an eightfold pattern at 2 K and 1.5 T. The anomalous pattern is discussed in terms of coexisting superconducting gap anisotropy and nonlocal effects.

Universal scaling of the Hall resistivity in MgB 2 superconductors

The mixed-state Hall resistivity

Synthesis of c-axis-oriented MgB2 thin films and the Hall effect

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Anomalous Paramagnetic Effects in the Mixed State of LuNi2B2C

and the longitudinal resistivity

Photoinduced Conductivity Dynamics Studies of MgB2 Thin Films

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Cooper pair breaking and superconducting state recovery dynamics in MgB/sub 2/ probed by time-resolved THz spectroscopy

in superconducting

Observation of Hall Scaling in MgB2 Thin Films

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Hall effect in c -axis-oriented MgB 2 thin films

thin films have been investigated as a function of the magnetic field over a wide range of current densities from

Specific heat study of the magnetic superconductorHoNi2B2C

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