TY - JOUR
T1 - Theory of triangular lattice quasi-one-dimensional charge-transfer solids
AU - Clay, R. T.
AU - Gomes, N.
AU - Mazumdar, S.
N1 - Funding Information:
S.M. acknowledges support from NSF-CHE-1764152. Some calculations in this work used the Extreme Science and Engineering Discovery Environment (XSEDE) [77] , which is supported by National Science Foundation Grant No. ACI-1548562. Specifically, we used the Bridges system [78] which is supported by NSF Award No. ACI-1445606, at the Pittsburgh Supercomputing Center (PSC) under award TG-DMR190052.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/9/27
Y1 - 2019/9/27
N2 - Recent investigations of the magnetic properties and the discovery of superconductivity in quasi-one-dimensional triangular lattice organic charge-transfer solids have indicated the severe limitations of the effective 12-filled band Hubbard model for these and related systems. We present computational studies within the 14-filled band Hubbard model for these highly anisotropic systems. Individual organic monomer molecules, and not their dimers, constitute the sites of the Hamiltonian within our theory. We find enhancement of the long-range component of superconducting pairing correlations by the Hubbard repulsive interaction U for band parameters corresponding to κ-(BEDT-TTF)2CF3SO3, which is superconducting under moderate pressure. We find significantly weaker superconducting pairing at realistic values of U in κ-(BEDT-TTF)2B(CN)4, and we ascribe the experimentally observed transition to a spin-gapped insulator to the formation of a paired-electron crystal. We make the testable prediction that the spin gap will be accompanied by charge ordering and period doubling in two lattice directions. The weaker tendency to superconductivity in κ-(BEDT-TTF)2B(CN)4 compared to κ-(BEDT-TTF)2CF3SO3 is consistent with the more one-dimensional character of the former. Pressure-induced superconductivity is, however, conceivable. The overall results support a valence bond theory of superconductivity we have proposed recently.
AB - Recent investigations of the magnetic properties and the discovery of superconductivity in quasi-one-dimensional triangular lattice organic charge-transfer solids have indicated the severe limitations of the effective 12-filled band Hubbard model for these and related systems. We present computational studies within the 14-filled band Hubbard model for these highly anisotropic systems. Individual organic monomer molecules, and not their dimers, constitute the sites of the Hamiltonian within our theory. We find enhancement of the long-range component of superconducting pairing correlations by the Hubbard repulsive interaction U for band parameters corresponding to κ-(BEDT-TTF)2CF3SO3, which is superconducting under moderate pressure. We find significantly weaker superconducting pairing at realistic values of U in κ-(BEDT-TTF)2B(CN)4, and we ascribe the experimentally observed transition to a spin-gapped insulator to the formation of a paired-electron crystal. We make the testable prediction that the spin gap will be accompanied by charge ordering and period doubling in two lattice directions. The weaker tendency to superconductivity in κ-(BEDT-TTF)2B(CN)4 compared to κ-(BEDT-TTF)2CF3SO3 is consistent with the more one-dimensional character of the former. Pressure-induced superconductivity is, however, conceivable. The overall results support a valence bond theory of superconductivity we have proposed recently.
UR - http://www.scopus.com/inward/record.url?scp=85072795711&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85072795711&partnerID=8YFLogxK
U2 - 10.1103/PhysRevB.100.115158
DO - 10.1103/PhysRevB.100.115158
M3 - Article
AN - SCOPUS:85072795711
SN - 0163-1829
VL - 100
JO - Physical Review B-Condensed Matter
JF - Physical Review B-Condensed Matter
IS - 11
M1 - 115158
ER -