2006/11/28 by Amit Ghosal, Pallab Goswami, Sudip Chakravarty · 5 citations
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Topological Materials and Phenomena #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.75.115123
published as Phys. Rev. B 75, 115123 (2007) · 11 pages, 2 eps figures
arxiv created 2006/11/28 · openalex publication_date 2007/03/22 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Free nodal fermionic excitations are simple but interesting examples of fermionic quantum criticality, in which the dynamic critical exponent z=1 and the quasiparticles are well defined. They arise in a number of physical contexts. We derive the scaling form of the diamagnetic susceptibility \ensuremathχ at finite temperatures and for finite chemical potential. From measurements in graphene, or in Bi_1\ensuremath-xSbx (x=0.04), one may be able to infer the striking Landau diamagnetic susceptibility of the system at the quantum critical point. Although the quasiparticles in the mean field description of the proposed d-density wave (DDW) condensate in high-temperature superconductors are another example of nodal quasiparticles, the crossover from the high-temperature behavior to the quantum critical behavior takes place at a far lower temperature due to the reduction of the velocity scale from the Fermi velocity vF in graphene to √vFvDDW, where vDDW is the velocity in the direction orthogonal to the nodal direction at the Fermi point of the spectra of the DDW condensate.