Bose-Einstein condensation of excitons in Cu sub 2 O

Miscellaneous · Mon Jan 01 00:00:00 EST 1990

OSTI ID:5352698

Snoke, D W

Free excitons provide the only experimental system other than helium in which the behavior of particles with mass is known to follow Bose-Einstein statistics. Experimental observations are presented of the kinetic energy distribution of excitons in the direct-gap semiconductor Cu{sub 2}O, both the triplet orthoexciton state and the singlet paraexciton state. The density and temperature of the exciton gas closely follow the phase boundary for Bose-Einstein condensation. At the highest densities, the lower-lying paraexcitons take on an anomalous energy distribution with a sharp, high-energy edge. This odd distribution of particle energies may be associated with Bose-Einstein condensation into a state with nonzero momentum. Indeed, the excitons leave the region of their creation at supersonic velocities. In addition to the experimental observations, theoretical models are presented for several aspects of this nonequilibrium system. The equilibration of a nearly-ideal boson gas is modeled, finding that a significant time is required for the approach to condensation. The temperature and density of the excitons in steady state are modeled based on known classical kinetic effects in semiconductors, and the effects of Bose-Einstein statistics on these processes estimated.

• Research Organization: Illinois Univ., Urbana, IL (United States)
• OSTI ID: 5352698
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COPPER OXIDES
EXCITONS
BOSE-EINSTEIN CONDENSATION
BOSE-EINSTEIN GAS
BOSE-EINSTEIN STATISTICS
ENERGY SPECTRA
SEMICONDUCTOR MATERIALS
CHALCOGENIDES
COPPER COMPOUNDS
MATERIALS
OXIDES
OXYGEN COMPOUNDS
QUASI PARTICLES
SPECTRA
TRANSITION ELEMENT COMPOUNDS
665430* - Other Topics in Quantum Fluids & Solids- (1992-)