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Front Cover: Quantum phase transitions in heavy fermion metals and Kondo insulators (Phys. Status Solidi B 3/2013)
Author(s) -
Si Qimiao,
Paschen Silke
Publication year - 2013
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201390006
Subject(s) - condensed matter physics , quantum critical point , quantum phase transition , physics , antiferromagnetism , fermi surface , quantum , quantum oscillations , quantum phases , fermi liquid theory , superconductivity , phase transition , quantum mechanics
The Review Article by Q. Si and S. Paschen ( pp. 425–438 ) addresses quantum phase transitions in strongly correlated electron systems. These are phase transitions occurring at absolute zero temperature, as function of a non‐thermal tuning parameter such as magnetic field, pressure, or doping. When the transitions are continuous, the accompanying quantum critical fluctuations drastically modify the materials properties at finite temperatures: they can turn a normal metal into a non‐Fermi liquid, or a poor conductor into an unconventional superconductor. The authors review the highly active theoretical and experimental research on quantum criticality in antiferromagnetic heavy fermion systems, and extend the discussion to less explored settings such as Kondo insulating, mixed valent, ferromagnetic, quadrupolar, or spin‐glass systems. A guiding principle is the distinction between “standard” quantum critical phenomena that fit into the textbook Landau framework, and “beyond Landau” quantum criticality. An example of the latter are quantum critical points that involve, in addition to the suppression of (magnetic) order, a destruction of Kondo entanglement and a concomitant jump of the Fermi surface. This distinction helps establish global phase diagrams to classify materials and their quantum criticality, and to advance their theoretical understanding.