TY - GEN
T1 - Observation of excitonic n-strings in a quasi-one-dimensional charge-transfer crystal
AU - Peyghambarian, N.
AU - Meissner, K.
AU - Fluegel, B.
AU - Mazumdar, S.
AU - Guo, F.
AU - Kuwata-Gonokami, M.
AU - Sato, Y.
AU - Ema, K.
AU - Shimano, R.
AU - Tokihiro, T.
AU - Ezaki, H.
AU - Hanamura, E.
PY - 1994
Y1 - 1994
N2 - Collective excitations, such as plasmons, rotons, electron-hole liquid, and excitonic molecules, have been extensively studied in condensed matter. Wannier excitons in inorganic semiconductors are bound by the exchange interactions between two electrons of the exciton, and the bound state of more than two excitons is not possible. We demonstrate here a new type of collective excitations, bound states of multiple charge-transfer (CT) excitons. Coulomb interactions in one dimension are shown to bind a train of several (more than two) CT excitons. Experimental evidence for these new type of elementary excitations is reported in a quasi-one-dimensional CT crystal of anthracene PMDA. High density excitation by femtosecond light pulses generates multi-exciton chains, which we refer to as excitonic n-strings with n = 1, 2, 3, etc., along the stack axis of the crystal. Both the n = 2 excitonic string (biexciton) and the n = 3 string (tri-exciton) are observed. This report provides evidence for an n>2 exciton chain in this system. The stability of the n-string exciton is supported by our theoretical calculations based on the extended Hubbard Hamiltonian in one dimension.
AB - Collective excitations, such as plasmons, rotons, electron-hole liquid, and excitonic molecules, have been extensively studied in condensed matter. Wannier excitons in inorganic semiconductors are bound by the exchange interactions between two electrons of the exciton, and the bound state of more than two excitons is not possible. We demonstrate here a new type of collective excitations, bound states of multiple charge-transfer (CT) excitons. Coulomb interactions in one dimension are shown to bind a train of several (more than two) CT excitons. Experimental evidence for these new type of elementary excitations is reported in a quasi-one-dimensional CT crystal of anthracene PMDA. High density excitation by femtosecond light pulses generates multi-exciton chains, which we refer to as excitonic n-strings with n = 1, 2, 3, etc., along the stack axis of the crystal. Both the n = 2 excitonic string (biexciton) and the n = 3 string (tri-exciton) are observed. This report provides evidence for an n>2 exciton chain in this system. The stability of the n-string exciton is supported by our theoretical calculations based on the extended Hubbard Hamiltonian in one dimension.
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M3 - Conference contribution
AN - SCOPUS:0028195606
SN - 1558992278
T3 - Materials Research Society Symposium Proceedings
SP - 683
EP - 688
BT - Electrical, Optical, and Magnetic Properties of Organic Solid State Materials
A2 - Garito, Anthony F.
A2 - Jen, Alex K-Y.
A2 - Lee, Charles Y-C.
A2 - Dalton, Larry R.
PB - Publ by Materials Research Society
T2 - Proceedings of the MRS 1993 Fall Meeting
Y2 - 29 November 1993 through 3 December 1993
ER -