TY - JOUR
T1 - Electronic structure and Fermi surface of the HgBa2CuO4+δ superconductor. Apparent importance of the role of van Hove singularities on high Tc
AU - Novikov, D. L.
AU - Freeman, A. J.
N1 - Funding Information:
We thank J.D. Jorgensen, D.G. Hinks, P.G Ra-daelli and A.J. Fedro Ibr helpful discussions and encouragement. This work was supported by the National Science Foundation (through the Northwestern University Science and Technology Center for Superconductivity, Grant No. DMR 92-20000, and by a grant of computer time at the NCSA. Champaign/Urbana, Illinois).
PY - 1993/7/1
Y1 - 1993/7/1
N2 - The electronic structure and Fermi surface of the recently discovered HgBa2CuO4+δ superconductor with Tc=95 K is calculated making use of the full-potential linear muffin-tin orbital (FLMTO) method. Similarly to the other high-Tc cuprates, the main feature of the electronic structure of undoped HgBa2CuO4 is a single free-electron-like-two-dimensional dpσ band crossing EF. As for the "infinite layered" compound, (Sr1-xCax)1-yCuO2 with Tc=110 K, the Fermi surface has the shape of a rounded square, and a major van Hove saddle-point singularity (vHS) exists near EF. Drastic changes of the density of states and Fermi surface are found when the hole doping moves the Fermi energy precisely onto the vHs, which is now seen to have a strong influence on the superconducting properties of this compound. These striking results also call attention to and provide possible support for vHs based excitonic pairing mechanisms for high Tc.
AB - The electronic structure and Fermi surface of the recently discovered HgBa2CuO4+δ superconductor with Tc=95 K is calculated making use of the full-potential linear muffin-tin orbital (FLMTO) method. Similarly to the other high-Tc cuprates, the main feature of the electronic structure of undoped HgBa2CuO4 is a single free-electron-like-two-dimensional dpσ band crossing EF. As for the "infinite layered" compound, (Sr1-xCax)1-yCuO2 with Tc=110 K, the Fermi surface has the shape of a rounded square, and a major van Hove saddle-point singularity (vHS) exists near EF. Drastic changes of the density of states and Fermi surface are found when the hole doping moves the Fermi energy precisely onto the vHs, which is now seen to have a strong influence on the superconducting properties of this compound. These striking results also call attention to and provide possible support for vHs based excitonic pairing mechanisms for high Tc.
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U2 - 10.1016/0921-4534(93)90509-O
DO - 10.1016/0921-4534(93)90509-O
M3 - Article
AN - SCOPUS:0027627520
SN - 0921-4534
VL - 212
SP - 233
EP - 238
JO - Physica C: Superconductivity and its applications
JF - Physica C: Superconductivity and its applications
IS - 1-2
ER -