Hybridization gap in the heavy-fermion compound UPd2Al3 via quasiparticle scattering spectroscopy
| Autor: | W. K. Park, Laura Greene, N. K. Jaggi, Omar Mehio, Paul H. Tobash, Ryan Baumbach, J. D. Thompson, M. Dwyer, Eve Bauer |
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| Rok vydání: | 2017 |
| Předmět: |
Superconductivity
Physics Condensed matter physics Scattering Magnon Transition temperature 02 engineering and technology 021001 nanoscience & nanotechnology 01 natural sciences Magnetic susceptibility Lattice (order) 0103 physical sciences Quasiparticle Antiferromagnetism 010306 general physics 0210 nano-technology |
| Zdroj: | Physical Review B. 95 |
| ISSN: | 2469-9969 2469-9950 |
| DOI: | 10.1103/physrevb.95.165123 |
| Popis: | We present results from point-contact spectroscopy of the antiferromagnetic heavy-fermion superconductor $\mathrm{UP}{\mathrm{d}}_{2}\mathrm{A}{\mathrm{l}}_{3}$: 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 cotunneling 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 $7.2\phantom{\rule{0.16em}{0ex}}\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0.16em}{0ex}}0.3\phantom{\rule{0.16em}{0ex}}\mathrm{meV}$ 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 \ensuremath{\sim}28 K, close to the temperature around which the magnetic susceptibility displays a broad peak, the conductance enhancement vanishes at \ensuremath{\sim}18 K, slightly above the antiferromagnetic transition temperature $({T}_{\mathrm{N}}\phantom{\rule{0.16em}{0ex}}\ensuremath{\approx}\phantom{\rule{0.16em}{0ex}}14\phantom{\rule{0.16em}{0ex}}\mathrm{K})$. 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 $5f$ 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 $5f$ dual-nature picture in the literature but also shed new light on the interplay between the itinerant and localized electrons in $\mathrm{UP}{\mathrm{d}}_{2}\mathrm{A}{\mathrm{l}}_{3}$. |
| Databáze: | OpenAIRE |
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