TY - JOUR
T1 - Anisotropic compressibility and effects of pressure on the electronic structure and Tc of Hg-based superconductors
AU - Novikov, D. L.
AU - Mryasov, O. N.
AU - Freeman, Arthur J
PY - 1994/3/10
Y1 - 1994/3/10
N2 - Total energy local density calculations of the effects of pressure on the HgBa2Can-1CunO2n+2+δ (n = 1,2,3) superconductors show that the compressibility is anisotropic. Estimates of the bond compressibilities show that the Cu-O(2) (apical) bond is extremely compressible, while the Hg-O(2) bond is the least compressible. A simple model is proposed to describe compressibilities of Hg-1212, Hg-1223 and Hg-1234 on the basis of results obtained for the infinite layer (Sr1-xCax)1-yCuO2 and Hg-1201 compounds. The energy location of the van Hove singularity (vHs) - important in several theories of high-Tc superconductivity - is found to move towards EF with pressure, thereby showing a correspondence between the number of holes (from dopants) needed to shift EF down to the vHs and the pressure needed to be applied to a fixed dopant material to achieve the best Tc. Some consequences for understanding the pressure effects on the Tc of the Hg superconductors and possible experiments are suggested.
AB - Total energy local density calculations of the effects of pressure on the HgBa2Can-1CunO2n+2+δ (n = 1,2,3) superconductors show that the compressibility is anisotropic. Estimates of the bond compressibilities show that the Cu-O(2) (apical) bond is extremely compressible, while the Hg-O(2) bond is the least compressible. A simple model is proposed to describe compressibilities of Hg-1212, Hg-1223 and Hg-1234 on the basis of results obtained for the infinite layer (Sr1-xCax)1-yCuO2 and Hg-1201 compounds. The energy location of the van Hove singularity (vHs) - important in several theories of high-Tc superconductivity - is found to move towards EF with pressure, thereby showing a correspondence between the number of holes (from dopants) needed to shift EF down to the vHs and the pressure needed to be applied to a fixed dopant material to achieve the best Tc. Some consequences for understanding the pressure effects on the Tc of the Hg superconductors and possible experiments are suggested.
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U2 - 10.1016/0921-4534(94)90112-0
DO - 10.1016/0921-4534(94)90112-0
M3 - Article
AN - SCOPUS:0028391914
VL - 222
SP - 38
EP - 46
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
IS - 1-2
ER -