相关论文: Giant exciton Mott density in anatase TiO2
Anatase TiO$_2$ is among the most studied materials for light-energy conversion applications, but the nature of its fundamental charge excitations is still unknown. Yet it is crucial to establish whether light absorption creates…
The Mott transition from a dipolar excitonic liquid to an electron-hole plasma is demonstrated in a wide GaN/(Al,Ga)N quantum well at $T=7$K by means of spatially-resolved magneto-photoluminescence spectroscopy. Increasing optical…
Exciton Mott transition in Si is investigated by using terahertz time-domain spectroscopy. The excitonic correlation as manifested by the 1s-2p resonance is observed above the Mott density. The scattering rate of charge carriers is…
Exciton many-body interaction bear great implication for application in advanced photonic devices and quantum science and technology such as quantum computing, but the fundamental understanding about exciton many-body interaction is very…
We have performed time-resolved terahertz absorption measurements on photoexcited electron-hole pairs in undoped GaAs quantum wells in magnetic fields. We probed both unbound- and bound-carrier responses via cyclotron resonance and…
The recent identification of strongly bound excitons in room temperature anatase TiO$_2$ single crystals and nanoparticles underscores the importance of bulk many-body effects in samples used for applications. Here, for the first time, we…
The coherent manipulation of excitons in bulk semiconductors via the lattice degrees of freedom is key to the development of acousto-optic and acousto-excitonic devices. Wide-bandgap transition metal oxides exhibit strongly bound excitons…
Indirect excitons in coupled quantum wells have long radiative lifetimes and form a cold quasi-two-dimensional population suitable for studying collective quantum effects. Here we report the observation of the exciton Mott transition from…
Photoluminescence spectra measured on a type-II GaSb/GaAs quantum dot ensemble at high excitation power indicate a Mott transition from the low density state comprising of spatially-indirect excitons to a high density electron-plasma state.…
We use two-color pump-probe spectroscopy to study Rydberg excitons in Cu$_2$O in the presence of free carriers injected by above-band-gap excitation. Already at plasma densities $\rho_\text{eh}$ below one hundredth electron-hole pair per…
We study carrier interaction induced many-body effects on the excitonic optical properties of highly photoexcited one-dimensional semiconductor quantum wire systems by solving the dynamically screened Bethe-Salpeter equation using realistic…
We report on the study of many-body interactions in a single high quality V-shaped quantum wire by means of continuous and time-resolved microphotoluminescence. The transition from a weakly interacting exciton gas when the carrier density n…
Exciton Mott physics in two-dimensional electron-hole (e-h) systems is studied in the quasiequilibrium, which is the crossovers or phase transitions between the insulating exciton gas and the metallic e-h plasma. By developing a…
Titanium dioxide (TiO2) is a wide-gap semiconductor with numerous applications in photocatalysis, photovoltaics, and neuromorphic computing. The unique functional properties of this material critically depend on its ability to transport…
When electron-hole pairs are excited in a semiconductor, it is a priori not clear if they form a fermionic plasma of unbound particles or a bosonic exciton gas. Usually, the exciton phase is associated with low temperatures. In atomically…
We report the observation of exciton formation from the cooled band-edge carriers in mixed two-dimensional hybrid organic-inorganic perovskites using femtosecond transient absorption spectroscopy. By monitoring the changes of bleach signal…
Many linked processes occur concurrently in strongly excited semiconductors, such as interband and intraband absorption, scattering of electrons and holes by the heated lattice, Pauli blocking, bandgap renormalization and the formation of…
Charge separated interlayer excitons in transition metal dichalcogenide (TMDC) heterobilayers are being explored for moir\'e exciton lattices and exciton condensates. The presence of permanent dipole moments and the poorly screened Coulomb…
We report a comprehensive experimental study and detailed model analysis of the terahertz dielectric response and density kinetics of excitons and unbound electron-hole pairs in GaAs quantum wells. A compact expression is given, in absolute…
In semiconductor physics, many essential optoelectronic material parameters can be experimentally revealed via optical spectroscopy in sufficiently large magnetic fields. For monolayer transition-metal dichalcogenide semiconductors, this…