Regensburg 2013 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 59: Correlated Electrons: Quantum-Critical Phenomena - Experiments

TT 59.1: Vortrag

Donnerstag, 14. März 2013, 15:00–15:15, H6

Quasi one-dimensional electronic structure of ferromagnetic heavy fermion YbNi₄P₂ — •Sven Friedemann¹, Swee K Goh¹, Michael Sutherland¹, F Malte Grosche¹, Cornelius Krellner², Christoph Geibel³, Helge Rosner³, Manuel Brando³, and Frank Steglich³ — ¹University of Cambridge, Cavendish Laboratory, CB3 0HE Cambridge, United Kingdom — ²Physikalisches Institut, Goethe-UniversitätFrankfurt, 60438 Frankfurt am Main, Germany — ³Max PlanckInstitute for Chemical Physics of Solids, 01187 Dresden, Germany

Quantum critical phenomena can be studied in great detail in lanthanide based heavy-fermion systems. Up to now, however, only materials with antiferromagnetic ground state were found. In the new heavy fermion material YbNi₄P₂ a clear ferromagnetic transition is observed at T_C = 0.17 K. YbNi₄P₂ has the prospect for studying ferromagnetic quantum criticality. Above the transition temperature strong evidence is found for the vicinity of YbNi₄P₂ to a quantum critical point: the specific heat diverges in a power-law form and the resistivity follows a linear temperature dependence. We present first Shubnikov-de Haas measurements in combination with electronic band structure calculations. The electronic structure is dominated by parallel disconnected sheets in accordance with the crystal structure featuring quasi-one-dimensional chains of Yb. The observed Shubnikov-de Haas oscillations are assigned to small quasi-two-dimensional portions of the Fermi surface. The experimentally observed mass enhancement of these orbits reflects the heavy-fermion character of YbNi₄P₂.