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Non‐Fermi‐liquid instabilities in non‐centrosymmetric heavy‐fermion CePtSi: A low‐temperature study
Author(s) -
Strydom A. M.,
Snyman J. L.,
Britz D.
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201200756
Subject(s) - fermi liquid theory , condensed matter physics , ground state , tetragonal crystal system , physics , paramagnetism , kondo effect , kondo insulator , fermi gamma ray space telescope , fermi level , superconductivity , quantum mechanics , electrical resistivity and conductivity , electron , phase (matter)
CePtSi is a known heavy‐fermion compound with no magnetic ordering. It forms in a tetragonal non‐centrosymmetric crystal structure. Pronounced Kondo features at elevated temperatures originate from magnetic Ce +3 ions. Towards low temperatures coherence develops in the electronic scattering and a Kondo lattice forms below 30 K. At the same temperature scale the electronic specific heat steeply escalates to C P / T ≃ 0.7 J mol −1 K −2 . Considerable effort has been devoted in previous studies to find the origin for the observed low‐temperature divergences in thermal properties in CePtSi and in particular for the putative non‐Fermi‐liquid behaviour. To date however, a coherent description of the physics of CePtSi remains to be found. In this work we present low‐temperature results of χ ( T ), C P ( T ), and ρ ( T ). A picture of the low‐temperature nature of this compound is forwarded that is consistent across the thermal properties. We illustrate how a non‐Fermi‐liquid state intervenes between the high‐temperature incoherent Kondo region and Kondo lattice ground state of CePtSi. The non‐Fermi‐liquid region effectively mediates a crossover from the high‐temperature paramagnetic state in CePtSi to its Fermi‐liquid ground state. We argue that magnetic ordering is avoided through a small but intrinsic dissimilarity between nearest‐neighbour Ce atoms.