Bibliographic Details
| Title: |
Hybridization gap in the heavy-fermion compound UPd$_2$Al$_3$ via quasiparticle scattering spectroscopy |
| Authors: |
Jaggi, N. K., Mehio, O., Dwyer, M., Greene, L. H., Baumbach, R. E., Tobash, P. H., Bauer, E. D., Thompson, J. D., Park, W. K. |
| Source: |
Phys. Rev. B 95, 165123 (2017) |
| Publication Year: |
2016 |
| Collection: |
Condensed Matter |
| Subject Terms: |
Condensed Matter - Strongly Correlated Electrons |
| More Details: |
We present results from point-contact spectroscopy of the antiferromagnetic heavy-fermion superconductor UPd$_2$Al$_3$: conductance spectra are taken from single crystals with two major surface orientations as a function of temperature and magnetic field, and analyzed using a theory of co-tunneling into an Anderson lattice. Spectroscopic signatures are clearly identified including the distinct asymmetric double-peak structure arising from the opening of a hybridization gap when a coherent heavy Fermi liquid is formed. Both the hybridization gap, found to be 7.2 $\pm$ 0.3 meV at 4 K, and the conductance enhancement above a flat background decrease upon increasing temperature. While the hybridization gap is extrapolated to remain finite up to $\sim$28 K, close to the temperature around which the magnetic susceptibility displays a broad peak, the conductance enhancement vanishes at $\sim$18 K, slightly above the antiferromagnetic transition temperature ($T_\textrm{N}$ $\approx$ 14 K). This rapid decrease of the conductance enhancement is understood as a consequence of the junction drifting away from the ballistic regime due to increased scattering off magnons associated with the localized U 5$f$ electrons. This shows that while the hybridization gap opening is not directly associated with the antiferromagnetic ordering, its visibility in the conductance is greatly affected by the temperature-dependent magnetic excitations. Our findings are not only consistent with the 5$f$ dual-nature picture in the literature but also shed new light on the interplay between the itinerant and localized electrons in UPd$_2$Al$_3$.
Comment: 28 pages, 8 figures, published in Phys. Rev. B |
| Document Type: |
Working Paper |
| DOI: |
10.1103/PhysRevB.95.165123 |
| Access URL: |
http://arxiv.org/abs/1610.08601 |
| Accession Number: |
edsarx.1610.08601 |
| Database: |
arXiv |
