Anomalous superconducting state gap size versus T-c behavior in underdoped Bi2Sr2Ca1-xDyxCu2O8+delta

被引:173
作者
Harris, JM
Shen, ZX
White, PJ
Marshall, DS
Schabel, MC
Eckstein, JN
Bozovic, I
机构
[1] STANFORD UNIV,STANFORD SYNCHROTRON RADIAT LAB,STANFORD,CA 94305
[2] VARIAN ASSOCIATES INC,GINZTON RES CTR,PALO ALTO,CA 94304
来源
PHYSICAL REVIEW B | 1996年 / 54卷 / 22期
关键词
D O I
10.1103/PhysRevB.54.R15665
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We report angle-resolved photoemission spectroscopy measurements of the excitation gap in underdoped superconducting thin films of Bi2Sr2Ca1-xDyxCu2O8-delta. As T-c is reduced by a factor of 2 by underdoping, the superconducting state gap Delta does not fall proportionally, but instead stays constant or increases slightly, in violation of the BCS mean-field theory result. The different doping dependences of Delta and KT2 indicate that they represent different energy scales. The measurements also show that a is highly anisotropic and consistent with a d(x2-y2) order parameter, as in previous studies of samples with higher dopings. However, in these underdoped samples, the anisotropic gap persists well above T-c. The existence of a normal state gap is related to the failure of Delta to scale with T-c in theoretical models that predict pairing without phase coherence above T-c.
引用
收藏
页码:15665 / 15668
页数:4
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共 30 条
  • [1] Theory of the spin gap in high-temperature superconductors
    Altshuler, BL
    Ioffe, LB
    Millis, AJ
    [J]. PHYSICAL REVIEW B, 1996, 53 (01): : 415 - 424
  • [2] THE RESONATING VALENCE BOND STATE IN LA2CUO4 AND SUPERCONDUCTIVITY
    ANDERSON, PW
    [J]. SCIENCE, 1987, 235 (4793) : 1196 - 1198
  • [3] THE RESONATING VALENCE BOND STATE AND HIGH-TC SUPERCONDUCTIVITY - A MEAN FIELD-THEORY
    BASKARAN, G
    ZOU, Z
    ANDERSON, PW
    [J]. SOLID STATE COMMUNICATIONS, 1987, 63 (11) : 973 - 976
  • [4] DISTINGUISHING D-WAVE SUPERCONDUCTORS FROM HIGHLY ANISOTROPIC S-WAVE SUPERCONDUCTORS
    BORKOWSKI, LS
    HIRSCHFELD, PJ
    [J]. PHYSICAL REVIEW B, 1994, 49 (21): : 15404 - 15407
  • [5] INFLUENCE OF THE SPIN GAP ON THE NORMAL STATE TRANSPORT IN YBA2CU4O8
    BUCHER, B
    STEINER, P
    KARPINSKI, J
    KALDIS, E
    WACHTER, P
    [J]. PHYSICAL REVIEW LETTERS, 1993, 70 (13) : 2012 - 2015
  • [6] MOMENTUM DEPENDENCE OF THE SUPERCONDUCTING GAP IN BI2SR2CACU2O8
    DING, H
    CAMPUZANO, JC
    BELLMAN, AF
    YOKOYA, T
    NORMAN, MR
    RANDERIA, M
    TAKAHASHI, T
    KATAYAMAYOSHIDA, H
    MOCHIKU, T
    KADOWAKI, K
    [J]. PHYSICAL REVIEW LETTERS, 1995, 74 (14) : 2784 - 2787
  • [7] Spectroscopic evidence for a pseudogap in the normal state of underdoped high-T-c superconductors
    Ding, H
    Yokoya, T
    Campuzano, JC
    Takahashi, T
    Randeria, M
    Norman, MR
    Mochiku, T
    Kadowaki, K
    Giapintzakis, J
    [J]. NATURE, 1996, 382 (6586) : 51 - 54
  • [8] LONG-RANGE COULOMB INTERACTIONS AND THE ONSET OF SUPERCONDUCTIVITY IN THE HIGH-TC MATERIALS
    DONIACH, S
    INUI, M
    [J]. PHYSICAL REVIEW B, 1990, 41 (10): : 6668 - 6678
  • [9] HIGH-TEMPERATURE SUPERCONDUCTING MULTILAYERS AND HETEROSTRUCTURES GROWN BY ATOMIC LAYER-BY-LAYER MOLECULAR-BEAM EPITAXY
    ECKSTEIN, JN
    BOZOVIC, I
    [J]. ANNUAL REVIEW OF MATERIALS SCIENCE, 1995, 25 : 679 - 709
  • [10] GROWTH OF UNTWINNED BI2SR2CA2CU3OX THIN-FILMS BY ATOMICALLY LAYERED EPITAXY
    ECKSTEIN, JN
    BOZOVIC, I
    SCHLOM, DG
    HARRIS, JS
    [J]. APPLIED PHYSICS LETTERS, 1990, 57 (10) : 1049 - 1051