Fermi surface dimensionality and superconducting critical temperature in heavy fermion compounds
Mardi 9 octobre 2018 13:30
- Duree : 1 heure
Lieu : LNCMI, salle de conférences "René Pauthenet" (bâtiment J, 2ème étage) - 25 rue des martyrs - 38000 Grenoble
Orateur : Ilya SHEIKIN (LNCMI)
The appearance of unconventional superconductivity in the vicinity of a quantum critical point (QCP) is a common trend in Ce-based heavy-fermion (HF) compounds. A more recent and still somewhat controversial issue is the influence of the Fermi-surface (FS) dimensionality on unconventional superconductivity. Indeed,
reduced dimensionality of the FS leads to nesting-type magnetic instabilities [1] and thus enhances the superconductivity [2, 3].
The family of CenTmIn3n+2m (T : transition metal, n = 1, 2, 3, m = 0, 1, 2) is an ideal candidate for a systematic study of the relation between Fermi surface dimensionality and superconducting properties. Unit cells within this family are composed of n layers of conducting CeIn3 separated by m layers of insulating TIn2. By increasing the ratio m=n, the spacing between the CeIn3 building blocks becomes larger, which is expected to augment two-dimensional behavior. Several compounds
of this family are superconductors either at ambient pressure or under pressure. The Fermi surfaces of some of them are already known. Recently, we mapped Fermi surfaces of two additional members, Ce2PdIn8 [4] and CePt2In7 [5], by de Haas-van Alphen measurements. In addition, we introduced a quantitative criterion of a quasi-two-dimensional Fermi surface deviation from an ideal cylinder. Built on this, I will discuss the relationship between Fermi surface dimensionality and superconducting critical temperature in heavy fermion materials.
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[2] P. Monthoux and G. G. Lonzarich, Phys. Rev. B 59, 14598 (1999).
[3] P. Monthoux, J. Phys. : Condens. Matter 15, S1973 (2003).
[4] K. Gotze, J. Klotz, D. Gnida, H. Harima, D. Aoki, A. Demuer, S. Elgazzar, J. Wosnitza, D. Kaczorowski, and I. Sheikin, Phys. Rev. B 92, 115141 (2015).
[5] K. Gotze, Y. Krupko, J. A. N. Bruin, J. Klotz, R. D. H. Hinlopen, S. Ota, Y. Hirose, H. Harima, R. Settai, A. McCollam, and I. Sheikin, Phys. Rev. B 96, 075138 (2017).
Contact : anne-laure.barra@lncmi.cnrs.fr
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