Anisotropic nonFermi liquids
Abstract
We study nonFermiliquid states that arise at the quantum critical points associated with the spin density wave (SDW) and charge density wave (CDW) transitions in metals with twofold rotational symmetry. We use the dimensional regularization scheme, where a onedimensional Fermi surface is embedded in (3 ∊ ) dimensional momentum space. In three dimensions, quasilocal marginal Fermi liquids arise both at the SDW and CDW critical points: the speed of the collective mode along the ordering wave vector is logarithmically renormalized to zero compared to that of Fermi velocity. Below three dimensions, however, the SDW and CDW critical points exhibit drastically different behaviors. At the SDW critical point, a stable anisotropic nonFermiliquid state is realized for small ∊ , where not only time but also different spatial coordinates develop distinct anomalous dimensions. The nonFermi liquid exhibits an emergent algebraic nesting as the patches of Fermi surface are deformed into a universal powerlaw shape near the hot spots. Due to the anisotropic scaling, the energy of incoherent spin fluctuations disperse with different power laws in different momentum directions. At the CDW critical point, on the other hand, the perturbative expansion breaks down immediately below three dimensions as the interaction renormalizes the speed of charge fluctuations to zero within a finite renormalization group scale through a twoloop effect. The difference originates from the fact that the vertex correction antiscreens the coupling at the SDW critical point whereas it screens at the CDW critical point.
 Publication:

Physical Review B
 Pub Date:
 November 2016
 DOI:
 10.1103/PhysRevB.94.195135
 arXiv:
 arXiv:1606.06694
 Bibcode:
 2016PhRvB..94s5135S
 Keywords:

 Condensed Matter  Strongly Correlated Electrons
 EPrint:
 27 pages, 15 figures