Theory of quasi-one and two-dimensional strongly correlated-electron systems, from semiconductors to superconductors, from their low temperature behavior to photo
and device physics. The collective behavior of such systems present physicists with some of the most challenging problems in condensed matter, including competing and co-existing spatial broken symmetries, metal-insulator transitions and unconventional superconductivity. The novel materials that we are trying to understand include superconducting organic charge-transfer solids, polycyclic aromatic hydrocarbon superconductors, high temperature oxide superconductors and two-dimensional systems with charge- and spin-frustration. In addition to broken symmetry I am interested in the photophysics of conjugated polymers, carbon nanotubes and carbon nanostructures. Strong Coulomb interactions between electrons and holes in these carbon-based semiconductors give excitons with unusually strong binding energies as the fundamental photoexcitation. The photophysics of these systems are of strong interest both because of the unusual nature of carbon-based semiconductors as well as their potential applications in organic lasers, solar cells and transistors. Much of our theoretical work in this latter area is performed in close collaborations with experimental colleagues with expertise in nonlinear optical spectrscopy and ultrafast spectroscopy.
Associated Western Universities Inc. Faculty Fellow 1991
Fellow of the American Physical Society, 2003
Henry and Phyllis Koffler Prize of the University of Arizona for Research, Scholarship and Creativity, 2006.
Outstanding Referee Physical Review 2010
R. T. Clay and S. Mazumdar, From charge- and spin-ordering to superconductivity in the organic charge-transfer solids, arXiv:1802.01551, to appear in Phys. Reports.
S. Khan and S. Mazumdar, Diagrammatic Exciton Basis Theory of the Photophysics of Pentacene Dimers, J. Phys. Chem. Lett. 8, 4468-4478 (2017).
Uyen N. V. Huynh, Tek P. Basel, Eitan Ehrenfreund, Gang Li, Yang Yang, S. Mazumdar, and Z. Valy Vardeny, Transient Magnetophotoinduced Absorption Studies of Photoexcitations in Pi-Conjugated Donor-Acceptor Copolymers, Phys. Rev. Lett. 119, 017401 (2017).
Niladri Gomes, W. Wasanthi De Silva, Tirthankar Dutta, R. Torsten Clay, and S. Mazumdar, Coulomb-enhanced superconducting pair correlations and paired-electron liquid in the frustrated quarter-filled band, Phys. Rev. B 93, 165110 (2016).
W. Wasanthi De Silva, N. Gomes, S. Mazumdar and R. T. Clay, Coulomb enhancement of superconducting pair-pair correlations in a 3/4-filled model for kappa-(BEDT-TTF)(2)X, Phys. Rev. B 93, 205111 (2016).