TY - JOUR
T1 - Coulomb enhancement of superconducting pair-pair correlations in a 34 -filled model for κ-(BEDT-TTF)2X
AU - De Silva, W. Wasanthi
AU - Gomes, N.
AU - Mazumdar, S.
AU - Clay, R. T.
N1 - Funding Information:
This work was supported by the US Department of Energy Grant No. DE-FG02-06ER46315. N.G. was supported by NSF Grant No. CHE-1151475. Part of the calculations were performed using resources of the National Energy Research Scientific Computing Center (NERSC), which is supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231.
Publisher Copyright:
© 2016 American Physical Society.
PY - 2016/5/9
Y1 - 2016/5/9
N2 - We present the results of precise correlated-electron calculations on the monomer lattices of the organic charge-transfer solids κ-(BEDT-TTF)2X for 32 and 64 molecular sites. Our calculations are for band parameters corresponding to X=Cu[N(CN)2]Cl and Cu2(CN)3, which are semiconducting antiferromagnetic and quantum spin liquid, respectively, at ambient pressure. We have performed our calculations for variable electron densities ρ per BEDT-TTF molecule, with ρ ranging from 1 to 2. We find that d-wave superconducting pair-pair correlations are enhanced by electron-electron interactions only for a narrow carrier concentration about ρ=1.5, which is precisely the carrier concentration where superconductivity in the charge-transfer solids occurs. Our results indicate that the enhancement in pair-pair correlations is not related to antiferromagnetic order, but to a proximate hidden spin-singlet state that manifests itself as a charge-ordered state in other charge-transfer solids. Long-range superconducting order does not appear to be present in the purely electronic model, suggesting that electron-phonon interactions also must play a role in a complete theory of superconductivity.
AB - We present the results of precise correlated-electron calculations on the monomer lattices of the organic charge-transfer solids κ-(BEDT-TTF)2X for 32 and 64 molecular sites. Our calculations are for band parameters corresponding to X=Cu[N(CN)2]Cl and Cu2(CN)3, which are semiconducting antiferromagnetic and quantum spin liquid, respectively, at ambient pressure. We have performed our calculations for variable electron densities ρ per BEDT-TTF molecule, with ρ ranging from 1 to 2. We find that d-wave superconducting pair-pair correlations are enhanced by electron-electron interactions only for a narrow carrier concentration about ρ=1.5, which is precisely the carrier concentration where superconductivity in the charge-transfer solids occurs. Our results indicate that the enhancement in pair-pair correlations is not related to antiferromagnetic order, but to a proximate hidden spin-singlet state that manifests itself as a charge-ordered state in other charge-transfer solids. Long-range superconducting order does not appear to be present in the purely electronic model, suggesting that electron-phonon interactions also must play a role in a complete theory of superconductivity.
UR - http://www.scopus.com/inward/record.url?scp=84968807185&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84968807185&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.93.205111
DO - 10.1103/PhysRevB.93.205111
M3 - Article
AN - SCOPUS:84968807185
VL - 93
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
SN - 0163-1829
IS - 20
M1 - 205111
ER -