Resonantly excited high-density exciton gas studiedvia broadbandTHz spectroscopy

Journal Article · Sat Jun 25 00:00:00 EDT 2005 · Physical Review B

DOI:https://doi.org/10.1103/PhysRevB.72.161314· OSTI ID:929083

Huber, Rupert; Kaindl, Robert A; Schmid, Ben A; Chemla, Daniel S

We report the density-dependent crossover of a resonantly photoexcited exciton gas from insulating to conducting phases. Broadband terahertz spectroscopy gives direct access to the exciton binding energy via intra-excitonic 1s-2p transitions. A strong shift, broadening, and ultimately the disappearance of this resonance occurs with decreasing inter-particle distance. Densities of excitons and unbound electron-hole pairs are followed quantitatively using a model of the composite free-carrier and exciton terahertz conductivity. Comparison with near-infrared absorption changes illustrates a significantly enhanced energy shift and broadening of the intra-excitonic resonance.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Director. Office of Science. Basic EnergySciences
• DOE Contract Number: DE-AC02-05CH11231
• OSTI ID: 929083
• Report Number(s): LBNL-58474; R&D Project: 504901; BnR: KC0202020; TRN: US0803465
• Journal Information: Physical Review B, Vol. 72; Related Information: Journal Publication Date: 2005
• Country of Publication: United States
• Language: English

Related Subjects

75
ABSORPTION
BINDING ENERGY
EXCITONS
RESONANCE
SPECTROSCOPY