超导与自旋涨落

　·40(2011)6　　　　　　　　　　　　　http:＊李世亮1,　　戴鹏程1,2(1　　　　100190)(2　　　　37996-1200)　　　,.,.,,.,.,、,,,..　　,,SuperconductivityandspinfluctuationsLI　Shi-Liang1,　　DAI　Peng-Cheng1,2(1　NationalLaboratoryforSuperconductivity,InstituteofPhysics,ChineseAcademyofSciences,Beijing100190,China)(2　DepartmentofPhysicsandAstronomy,TheUniversityofTennessee,Tennessee37996-1200,USA)Abstract　　Inconventionalsuperconductors,Cooperpairsaremediatedbyphonons,whichisaprocesswhereonlythecorrelationsbetweenthephononsandthechargepropertiesoftheelectronsareneeded.However,so-calledunconventionalsuperconductivitycanalsobederivedfromothertypesofelementaryexcitations.Themostpromisingcandidatethatcanmediatesuchunconventionalsuperconductivityisspinfluctuations.Insomeimportantsystemssuchascuprates,Fe-basedsuperconductorsandcertainheavy-fermionsuperconductors,thespinfluctuationsplayakeyroleinunderstandingthemechanismoftheirsuperconductivityalthoughthereisstillmuchdebate.Inthispaperwepresentabriefreviewofthecorrela-tionbetweenspinfluctuationsandsuperconductivity.Keywords　　unconventionalsuperconductivity,spinfluctuations,neutronscattering＊　(:2010CB833102;2010CB923002)2011-04-20.Email:[e-mail]1　引言,,.,,,,.,,,.,,..,,.,,..,、、、,..·353·100http:　　　　　　　　　　　　　　　　　　·40(2011)6.,“”.,,,..,.2.3(、),,.,[1].,,d2σdΨdω∝F2(Q)1-exp-ωkBTχ″(Q,ω),(1)F(Q)..2　常规超导体中的自旋涨落BCS.,().,,(1,I).,,.,.,,()(s,d,…);,,(p,f,…).s,..,,.,,.V3Si,[2].1　(TcHc)3　非常规超导体中的自旋涨落,,.2070,,,.,.,.,.,().,Tc,Tc,,,..3.1　().,.,[3].2(a)[4].·354·100　·40(2011)6　　　　　　　　　　　　　http:(),.,,.,La2-xSrxCuO4,().,,Tc.,,,(ab)(c).,c,,.,.,La2-xSrxCuO4,,[5]..2(a)[4];(b)Ba(Fe1-xCox)2As2[10];(c)(TMTTF)2PF6[21];(d)NaxCoO2[22],.,,,,3(a)[6].,,Tc,,3(b)[7].,、、,.,Tc,Tc,3(c).,.3(a)YBa2Cu3O6.93(YBCO)(I(11K)I(100K)[6]);(b)YBCO[7];(c)Tc(,).,Tc,.,,[8].,(,3.3),,Tc.,,,.,,,[9]..55K,Tc,.2(b)Ba(Fe1-xCox)2As2[10].,,,·355·100http:　　　　　　　　　　　　　　　　　　·40(2011)6.,.,.,..,2(a),2(b).,.,[11].,,,,[12].,3(c),.,BaFe1.92Ni0.08As2,,[13].,.,CeCoIn5,[14].3(c).,.,CeCoIn5(Tc=2.3K),.,Er(0.6meV),Er/Tc.,Er/2Δ[15].3,,d,f;d,s.,“”,-[16].Er/2Δ.,1,,.,,(、),,.:,,,.,.UPd2Al3UNi2Al3,0.85μB0.24μB,.,UPd2Al3、,;UNi2Al3、,.UPd2Al3,,Tc,4(a)[17].,UPt3(Tc=0.5K),20K,5K,0.01—0.03μB,(2μB),.UPt3,,,,.URu2Si2,,.,UBe13,20K.,CenMmIn3n+2m(M=Co,Ir,Rh),CeM2X2(M=Cu,Au,Rh,Pd,Ni;X=Si,Ge),Ce.,.4(b)4(c)CeMIn5(M=Co,RhIr)[18]CeCu2(Si1-xGex)2[19],,,.Ce,CenMmIn3n+2mTc,,.,,CeCoIn5.,CeCu2Si2,·356·100　·40(2011)6　　　　　　　　　　　　　http:(4(d)),[20].4(a)UPd2Al3[17],Tc.,;(b)CeMIn5[18](xCeMIn5);(c)CeCu2(Si1-xGex)2[19];(d)CeCu2Si2,[20](QAF,).,().,()Tc,.2(c)(TMTTF)2PF6[21],,.κ-Cu[N(CN)2]Cl.,、.,.,、,,,..,,.,NaxCoO2,,,(2(d))[22].,1/4x1/3.,[23].,.β-MNX(M=Ti,Zr,Hf;X=Cl,Br,I),Tc25K.,[24],,.3.2　,,2,,()..,,,.,.,.,:,.UGe2,5(a)[25].,.f,,.,,.,Tx,,,Tx.Tx,2..,..UGe2URhGe,.UCoGeUIr,.,.La2-xSrxCuO4,,Sr2RuO4.,,,p,·357·100http:　　　　　　　　　　　　　　　　　　·40(2011)65　(a)UGe2[25](Ts10.Tc);(b)Ca2-xSrxRuO4[26](Sr2RuO4).Ca,,5(b)[26].Ca,.Sr2RuO4,0.2≤x≤1.5Ca2-xSrxRuO4,[27].,,.3.3　,.,,,..,La2-xBaxCuO4,Tcx=1/8.,“”.,,,,1/8,6(a),.,[28],、Tc[29].,6(b)“”[30].,.,La2-xSrxCuO4(),“”.,“”,,.,d..6　(a)(,.:,1/8);(b)[30]((0.5±δ,0.5)(0.5,0.5±δ),δ(0.5,0.5));(c)URu2Si2[36];(d)URu2Si21.5K()[37]((2,0,0))“”[31]..“”,,.(),,,..,.,YBCO[32].,[33].,,,,,[34,35].,.,UGe2,.,,、(spin-Peierlsstate).、、·358·100　·40(2011)6　　　　　　　　　　　　　http:、,,.NaxCoO2,.,,,.URu2Si2.6(c)[36].,,T0,,.,0.03μB,T0,(0.4μB).,,T0(6(d))[37].“”,[38].,,,,.4　结论1972BCS,,2070()..,.,,.,“”,BCS,.,,.[1]　,.,2011,40:33[LiSL,DaiPC.Wuli(Physics),2011,40:33][2]　ShullCGetal.Phys.Rev.Lett.,1966,16:513[3]　,.,2006,35:837[DaiPC,LiSL.Wuli(Physics),2006,35:837][4]　OrensteinJetal.Science,2000,288:468[5]　WakimotoSetal.Phys.Rev.Lett.,2007,98:247003[6]　DaiPetal.Phys.Rev.B,2001,63:054525[7]　DaiPetal.Science,1999,284:1344[8]　LakeBetal.Nature,2002,415:299[9]　BarthAetal.J.Supercond.Nov.Magn.,2008,21:113[10]　ChuJHetal.Phys.Rev.B,2009,79:014506[11]　,.,2009,38:644[LiSL,DaiPC.Wuli(Physics),2009,38:644][12]　LumsdenMDetal.J.Phys.:Condens.Matter,2010,22:203203[13]　WangMetal.Phys.Rev.B,2011,83:094516[14]　StockCetal.Phys.Rev.Lett.,2008,100:087001[15]　YuGetal.Nat.Phys.2009,5:873[16]　EschrigM.Adv.Phys.,2006,55:47[17]　BernhoeftBetal.Phys.Rev.Lett.,1998,81:4244[18]　SarraoJLetal.J.Phys.Soc.Jpn.,2007,76:051013[19]　ThalmeierPetal.FrontiersinMagneticMaterials/FrontiersinSuperconductiveMaterialsVol.XXXII(SpringerVerlag,Berlin),109[20]　StockertOetal.Nat.Phys.,2011,7:119[21]　JaccardDetal.J.Phys:Condens.Matter,2001,13:89[22]　FooMLetal.Phys.Rev.Lett.,2004,92:247001[23]　SatoMetal.J.Mag.Mag.Mater.,2007,310:666[24]　KasaharaYetal.Phys.Rev.Lett.,2009,103:077004[25]　SaxenaSSetal.Nature,2000,406:587[26]　NakatsujiSetal.Phys.Rev.Lett.,2000,84:2666[27]　SteffensPetal.Phys.Rev.B,2011,83:054429[28]　TranquadaJMetal.Nature,1995,375:561[29]　YamadaKetal.Phys.Rev.B,1998,57:6165[30]　JMTranquadainHandbookofHigh-TemperatureSupercon-ductivity(Springer,NewYork,2007),257[31]　KivelsonSAetal.Nature,1998,393:550[32]　HinkovVetal.Science,2008,319:597[33]　HarrigerLWetal.arXiv:1011.3771[34