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TT: Fachverband Tiefe Temperaturen
TT 11: Heavy Fermions
TT 11.1: Vortrag
Montag, 18. März 2024, 15:00–15:15, H 3005
Controlling crystal-electric field levels through symmetry-breaking uniaxial pressure in a cubic super heavy fermion — •Elena Gati1, Burkhard Schmidt1, Sergey L. Bud’ko2, Andrew P. Mackenzie1,3, and Paul C. Canfield2 — 1MPI for Chemical Physics of Solids, 01187, Dresden, Germany — 2Ames National Laboratory, US DOE, and Physics Dept., Iowa State University, Ames, IA, 50011, USA — 3Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, UK
YbPtBi is one of the heavy-fermion systems with largest Sommerfeld coefficient γ and is thus classified as a ’super’-heavy fermion material. In this work, we resolve the long-debated question about the crystal-electric field (CEF) level scheme in YbPtBi, by deliberate breaking of its cubic symmetry through uniaxial pressure tuning. Through measurements of the novel a.c. elastocaloric effect and generic symmetry arguments, we identify an elastic level splitting under uniaxial pressure that is unambiguously associated with the symmetry-allowed splitting of a quartet CEF level at Δ/kB ≈ 1.6 K. Our study shows the potential of the a.c. elastocaloric effect to control and quantify strain-induced changes of the CEF schemes, opening a different route to disentangle the CEF energy scales from other relevant energy scales in correlated quantum materials.
Work is supported by the DFG through TRR 288 (ID 422213477) and the SFB 1143 (ID 247310070).
[1] Gati et al., npj Quant. Mat. 8 (2023) 69.
Keywords: Heavy fermions; Strain Tuning