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.
END
