Evidence for Charge Kondo Effect in Superconducting Tl-Doped PbTe Y. Matsushita,1 H. Bluhm,2 T. H. Geballe,3 and I. R. Fisher3 1Department of Materials Science and Engineering and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305-4045, USA 2Department of Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305-4045, USA 3Department of Applied Physics and Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305-4045, USA (Received 9 September 2004; published 21 April 2005)

Charge Kondo Effect and Superconductivity in Tl-Doped PbTeY. Matsushita,et.al. PRL 94 , 157002 (2005)T. A. Costi and V. ZlaticPRL 108, 036402 (2012)Hiroyasu MATSUURA and Kazumasa MIYAKE 81 (2012) 113705KITAOKA.LAB.MMAKISHOUTAContentsHistory of SuperconductivityProperties of PbTeKondo effectValence Skipper (ex:Tl)Experimental reportSummaryHistory of Superconductivityunder high pressure050100150200SmO0.9F0.11FeAsLaO0.89F0.11FeAsLaOFePHg-Ba-Ca-Cu-OHg-Ba-Ca-Cu-OTl-Ba-Ca-Cu-OBi-Sr-Ca-Cu-OY-Ba-Cu-OMgB2NbGeNbNNbCNbPbhigh-Tc cupratemetaliron-based systemTransition temperature (K) 1900192019401960198020002020YearHgLa-Ba-Cu-ODiscovery of superconducting phenomenon

19111986High-Tc cuprate superconductor2006Iron-based high-Tc superconductor771631979Heavy fermion superconductorCeCu2Si2heavy fermion systemPuCoGa5Properties of PbTe

NaCl structure, (space group Fm3m) Pb2+ (6s26p2-2) ,Te2-(5s25p4+2)

PbTe : Eg(4.2K)=0.119eVPbTe : Eg(300K)=0.31eVSi : Eg(300K)=1.11eVGe : Eg(300K)=0.67eVTl-doping is hole doping to valence band0.646nmSC in Tl-Doped PbTe

TcX=0Tl-Doped PbTe

0

X=1.3%X=0.8%X=0.4%

X=0.3%

X=0.2%X=0.1%X=0%0min

0min

0Ximpurity densityIncrease of resistivity(0min)

Kondo effectThe Kondo effect is caused by dilute magnetic impurities in a nonmagnetic hostFermi SeaLocalized electronConduction electronSpin singletKondo effectThe Kondo effect is caused by dilute magnetic impurities in a nonmagnetic hostFermi SeaLocalized electronConduction electron

Kondo effectThe Kondo effect is caused by dilute magnetic impurities in a nonmagnetic hostFermi SeaLocalized electronConduction electron

Valence Skipper-TlEnergy HighLowTl+1Tl+2Tl+3Tl+1Tl+3Tl+26s6pTlTl1+Tl2+Tl3+Tl1+ and Tl3+ have no magnetic momentWhy did we expect for Kondo-like behavior? -2e0eExperimental Report 1

Pr1-xLaxPb3

Pb1-xTlxTe

It Isnt based on Spin-Kondo effect but Chage Kondo effect!!Ex)Kondo effect

Valence Skipper -Tl

En : total energy of n+ ionic stateUn : effective intra-atomic Coulomb repulsion for n+ ionic stateU(ns1) < U(ns0), U(ns2)For valence skipperElectron in ns1 state feels effectively intra-atomic attraction Negative U (attractive force between electrons)

image6.46About 16Negative UAttractive force between electronsCharge fluctuation causes SC?X=1%2-dimensionsBehavior of electron in Tl-Doped PbTe

Negative UAttractive force between electronsCharge fluctuation causes SC?0e0e-2e6.46About 16imageX>25%Behavior of electron in Tl-Doped PbTe

Negative UAttractive force between electronsCharge fluctuation causes SC?imageX>25%SummaryPbTe is semi-conductor (narrow gap ). But Pb1-xTlxTe(X>0.3%) became SC.

low-temperature resistivity upturn is observed by only Pb1-xTlxTe(X>0.3%) . This behavior can be understood by Charge Kondo effect So the theory predicts that Charge Kondo effect relates to SC.

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