First Principle Calculation of Lattice, Electronic Structures and Hole Concentration of Ca-Doped YBCO

Abstract:

This work analyzes the lattice, electronic structures and hole concentration of calcium-doped YBCO compounds using density functional theory. The investigation was conducted on two models, Y_0.875Ca_0.125Ba₂Cu₃O₇ (YCa123) and Y_0.875Ca_0.125Ba₂Cu₄O₈ (YCa124), using density functional theory. The results reveal that calcium substitution induces changes in the lattice structure, including a decrease in the lattice constant and a distortion of the Cu-O₂ plane. Furthermore, the electronic structure was also altered, leading to changes in the density of states above the Fermi level. The hole concentrations were also calculated and were found to be 0.19 and 0.16 for YCa123 and YCa124, respectively. These results indicate that the hole concentration of YCa124 is lower than that of YCa123, consistent with the parabolic curve relationship between hole concentration and superconducting transition temperature. The results suggest that Cu (2) atoms fluctuate between the states of Cu⁺ and Cu²⁺, which may be crucial for understanding electron-electron pairing mechanism. These results could aid in the development of more efficient and practical superconducting materials through targeted doping strategies.

• Periodical: Materials Science Forum (Volume 1144)
• Pages: 3-9
• DOI: https://doi.org/10.4028/p-rzHE9K
• Online since: March 2025
• Authors: Choon Min Cheong*, Soo Kien Chen
• Keywords: Ca-YBCO, Density Functional Theory, Density of State, Y-123, YBCO

References

[1] Sedky A, Abu-Ziad B. New investigation for Tc depression by Ca in Y1-xCax:123 superconducting systems. Phys C Supercond its Appl. 2010;470:659-668

DOI: 10.1016/j.physc.2010.03.015

[2] Miyachi Y, Funaki S, Yamada Y. Increasing the Tc of YBa2Cu4O8 to 90 K by Sr substitution via the KOH flux method. Jpn J Appl Phys. 2019;58:070906

DOI: 10.7567/1347-4065/ab2a3b

[3] Stewart GR. Unconventional superconductivity. Adv Phys. 2017;66:75-196

DOI: 10.1080/00018732.2017.1331615

[4] Torrance JB, Bezinge A, Nazzal AI, et al. Properties that change as superconductivity disappears at high-doping concentrations in La2-xSrxCuO4. Phys Rev B. 1989;40:8872-8877

DOI: 10.1103/PhysRevB.40.8872

[5] Tallon JL, Bernhard C, Shaked H, Hitterman RL, Jorgensen JD. Generic superconducting phase behavior in high-Tc cuprates: Tc variation with hole concentration in YBa2Cu3O7-δ. Phys Rev B. 1995;51:12911-12914

DOI: 10.1103/PhysRevB.51.12911

[6] Presland MR, Tallon JL, Buckley RG, Liu RS, Flower NE. General trends in oxygen stoichiometry effects on Tc in Bi and Tl superconductors. Phys C. 1991;176:95-105.

DOI: 10.1016/0921-4534(91)90700-9

[7] Tallon JL. Time-dependent charge transfer and the superconducting phase diagram for YBa2Cu3O7-x. Phys C. 1991;176:547-550.

DOI: 10.1016/0921-4534(91)90062-4

[8] Lee SC, Lee JH, Suh BJ, Moon SH, Lim CJ, Z. G. Khim. Thermoelectric power and superconducting properties of YBa2Cu3O7-6 and RBa2Cu3O7-6. Phys Rev B. 1988;37(4):2285-2288

DOI: 10.1103/PhysRevB.37.2285

[9] Mori K, Kawaguchi Y, Ishigaki T, Katano S, Funahashi S, Hamaguchi Y. Crystal structure and critical temperature of RBa2Cu4O8 (R = Tm, Er, Ho, Y, Dy and Gd). Phys C Supercond its Appl. 1994;219:176-182

DOI: 10.1016/0921-4534(94)90031-0

[10] Giannozzi P, Baroni S, Bonini N, et al. QUANTUM ESPRESSO: A modular and open-source software project for quantum simulations of materials. J Phys Condens Matter. 2009;21:395502

DOI: 10.1088/0953-8984/21/39/395502

[11] Marzari N, Vanderbilt D, Vita A De, Payne MC. Thermal Contraction and Disordering of the Al(110) Surface. Phys Rev Lett. 1999;82(16):3296

DOI: 10.1103/PhysRevLett.82.3296

[12] Perdew JP, Burke K, Ernzerhof M. Generalized Gradient Approximation Made Simple. Phys Rev Lett. 1996;77(18):3865-3868

DOI: 10.1103/PhysRevLett.77.3865

[13] Broyden CG. The convergence of a class of double-rank minimization algorithms 1. General considerations. IMA J Appl Math (Institute Math Its Appl. 1970;6:76-90

DOI: 10.1093/imamat/6.1.76

[14] Cheong CM, Chen SK. (2023). First Principle Calculation of Electronic Structures and Hole Concentration of YBCO Family Compounds. AIP Conf Proc. Advance online publication.

[15] Cheong CM, Rahman MM, Shaari AH, Chen SK. Charge distribution in YBa2Cu3O7 and YBa2Cu4O8 by density functional theory. Mater Sci Forum. 2016;846:561-566

DOI: 10.4028/www.scientific.net/MSF.846.561

[16] Krakauer H, Pickett WE, Cohen RE. Analysis of electronic structure and charge density of the high-temperature superconductor YBa2Cu3O7. J Supercond. 1988;1:111-141

DOI: 10.1007/BF00617955

[17] Murphy ST. A point defect model for YBa2Cu3O7 from density functional theory. J Phys Commun. 2020;4(11):1-14

DOI: 10.1088/2399-6528/abc9a7

[18] Cava RJ, Hewat AW, Hewat EA, et al. Structural Anomilies Oxygen Ordering and Superconductivity in Oxygen Deficient Ba2YCu3Ox. Phys C. 1990;165:419-433.

DOI: 10.1016/0921-4534(90)90376-p

[19] Papaconstantopoulos DA. Handbook of the Band Structure of Elemental Solids From Z = 1 To Z = 112. Second Edi. Springer; 2015

DOI: 10.1007/978-1-4419-8264-3_1

[20] Ramli A, Shaari AH, Baqiah H, Kean CS, Kechik MMA, Talib ZA. Role of Nd2O3 nanoparticles addition on microstructural and superconducting properties of YBa2Cu3O7-δ ceramics. J Rare Earths. 2016;34:895-900

DOI: 10.1016/S1002-0721(16)60112-6

[21] Hapipi NM, Chen SK, Shaari AH, et al. AC Susceptibility of BaZrO3 Nanoparticles Added YBa2Cu3O7−δ Superconductor Prepared via Coprecipitation Method. J Supercond Nov Magn. 2019;32:1191-1198

DOI: 10.1007/s10948-018-4829-y

[22] Chu CW, Deng LZ, Lv B. Hole-doped cuprate high temperature superconductors. Phys C Supercond its Appl. 2015;514:290-313

DOI: 10.1016/j.physc.2015.02.047

[23] Zhang J, Botana AS, Freeland JW, et al. Large orbital polarization in a metallic square-planar nickelate. Nat Phys. 2017;13(9):864-869

DOI: 10.1038/nphys4149

[24] Liu Z, Xu C, Cao C, Zhu W, Wang ZF, Yang J. Doping dependence of electronic structure of infinite-layer NdNiO2. Phys Rev B. 2021;103(4):1-10

DOI: 10.1103/PhysRevB.103.045103