Singular or non-Fermi liquids

268C.M.Varmaetal./PhysicsReports361(2002)267–417

338341343343344353359360361361364

7.3.Generalrequirementsinamicroscopic

theory

7.4.Microscopictheory

8.Themetallicstateintwodimensions8.1.Thetwo-dimensionalelectrongas8.2Non-interactingdisorderedelectrons:

scalingtheoryoflocalization

8.3.Interactionsindisorderedelectrons8.4.Finkelsteintheory

pressibility,screeninglengthand

amechanismformetal–insulatortransition8.6.Experiments

8.7.Discussionoftheexperimentsinlight

ofthetheoryofinteractingdisorderedelectrons

8.8.PhasediagramandconcludingremarksAcknowledgementsReferences

372373379380381385389391392400404406406

5.1.SFLbehaviorduetocouplingtothe

electromagneticÿeld

5.2.Generalizedgaugetheories

6.Quantumcriticalpointsinfermionicsystems

6.1.Quantumcriticalpointsin

ferromagnets,antiferromagnets,andchargedensitywaves6.2.Quantumcriticalscaling

6.3.ExperimentalexamplesofSFLdue

toquantumcriticality:opentheoreticalproblems

6.4.Specialcomplicationsinheavy

fermionphysics

6.5.E ectsofimpuritiesonquantum

criticalpoints

7.Thehigh-Tcprobleminthecopper-oxide-basedcompounds

7.1.Somebasicfeaturesofthehigh-Tc

materials

7.2.MarginalFermiliquidbehaviorofthe

normalstate

Abstract

Anintroductorysurveyofthetheoreticalideasandcalculationsandtheexperimentalresultswhichde-partfromLandauFermiliquidsispresented.ThecommonthemesandpossibleroutestothesingularitiesleadingtothebreakdownofLandauFermiliquidsarecategorizedfollowinganelementarydiscussionofthetheory.Solubleexamplesofsingularornon-Fermiliquidsincludemodelsofimpuritiesinmetalswithspecialsymmetriesandone-dimensionalinteractingfermions.AreviewoftheseisfollowedbyadiscussionofsingularFermiliquidsinawidevarietyofexperimentalsituationsandtheoreticalmodels.Theseincludethee ectsoflow-energycollective uctuations,gaugeÿeldsdueeithertosymmetriesintheHamiltonianorpossibledynamicallygeneratedsymmetries, uctuationsaroundquantumcriticalpoints,thenormalstateofhigh-temperaturesuperconductorsandthetwo-dimensionalmetallicstate.Forthelastthreesystems,theprincipalexperimentalresultsaresummarizedandtheoutstandingtheoretical

c2002ElsevierScienceB.V.Allrightsreserved.issuesarehighlighted.

PACS:7.10.Ay;71.10.Hf;71.10.Pm;71.27.+a