Tunneling current-voltage characteristics (CVC) are calculated for symmetrical and nonsymmetrical junctions made up of metals with charge-density or spin-density waves and a distortion of the Fermi-surface nesting sections described by the order parameter Σ. For the symmetrical junction the CVC are odd functions of the bias voltage V and do not depend on the sign of Σ. The differential conductivities have root singularities at eV=Σ and jumps at eV=2Σ. For the nonsymmetrical junction the CVC depend on the sign of Σ. Relevant differential conductivities are nonsymmetrical, with one branch being smooth and another having a root singularity at eV=Σ. A qualitative agreement exists with the tunneling and point-contact spectroscopy measurements for layered dichalcogenides, ${\mathrm{NbSe}}_3$, and ${\mathrm{URu}}_2$${\mathrm{Si}}_2$.

• Received 21 December 1994

DOI:https://doi.org/10.1103/PhysRevB.52.7437