title: Strong Quantum Coherence between Fermi Liquid Mahan Excitons.
abstract: In modulation doped quantum wells, the excitons are formed as a result of the interactions of the charged holes with the electrons at the Fermi edge in the conduction band, leading to the so-called "Mahan excitons." The binding energy of Mahan excitons is expected to be greatly reduced and any quantum coherence destroyed as a result of the screening and electron-electron interactions. Surprisingly, we observe strong quantum coherence between the heavy hole and light hole excitons. Such correlations are revealed by the dominating cross-diagonal peaks in both one-quantum and two-quantum two-dimensional Fourier transform spectra. Theoretical simulations based on the optical Bloch equations where many-body effects are included phenomenologically reproduce well the experimental spectra. Time-dependent density functional theory calculations provide insight into the underlying physics and attribute the observed strong quantum coherence to a significantly reduced screening length and collective excitations of the many-electron system.
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: J
authors.initials: J
authors.lastname: Paul
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: C E
authors.initials: CE
authors.lastname: Stevens
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: C
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: P
authors.initials: P
authors.lastname: Dey
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: C
authors.initials: C
authors.lastname: McIntyre
authors.affiliation: Department of Physics, University of Central Florida, Orlando, Florida 32816, USA.
authors.forename: V
authors.initials: V
authors.lastname: Turkowski
authors.affiliation: CINT, Sandia National Laboratories, Albuquerque, New Mexico 87185, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Reno
authors.affiliation: Department of Physics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Hilton
authors.affiliation: Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, Florida 33620, USA.
authors.forename: D
authors.initials: D
authors.lastname: Karaiskaj