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Excitons in semiconductors may form correlated phases at low temperatures. We report the observation of an exciton liquid in GaAs/AlGaAs coupled quantum wells. Above a critical density and below a critical temperature the photogenerated…
We study ultra-cold dipolar excitons confined in a 10$\mu$m trap of a double GaAs quantum well. Based on the local density approximation, we unveil for the first time the equation of state of excitons at pure thermodynamic equilibrium. In…
We study the fluorescence light emitted from GaAs excitons in semiconductor quantum wells. The excitons are modeled as interacting bosons. By combining quantum optical methods for the excitonic emission spectrum with many particle…
One of the most striking quantum effects in a low temperature interacting Bose gas is superfluidity. First observed in liquid 4He, this phenomenon has been intensively studied in a variety of systems for its amazing features such as the…
We study dipolar excitons confined at 330 mK in a square electrostatic lattice of a GaAs double quantum well. In the dipolar occupation blockade regime, at 3/2 filling, we evidence that excitons form a face-centred superlattice quantum…
Combining the capabilities of gate defined quantum transport devices in GaAs-based heterostructures and of optically addressed self-assembled quantum dots could open broad perspectives for new devices and functionalities. For example,…
We study semiconductor excitons confined in an electrostatic trap of a GaAs bilayer heterostructure. We evidence that optically bright excitonic states are strongly depleted while cooling to sub-Kelvin temperatures. In return, the other…
We report a two-dimensional artificial lattice for dipolar excitons confined in a GaAs double quantum well. Exploring the regime of large fillings per lattice site, we verify that the lattice depth competes with the magnitude of excitons…
We study spatially indirect excitons confined in a 10 $\mu$m wide electrostatic trap of a GaAs double quantum well. We introduce a technique to control the amplitude of the electric field interacting with the excitons electric dipole, with…
Singly quantized vortices have been already observed in many systems including the superfluid helium, Bose Einstein condensates of dilute atomic gases, and condensates of exciton polaritons in the solid state. Two dimensional superfluids…
A giant built-in electric field in the growth direction makes excitons in wide GaN/(Al, Ga)N quantum wells spatially indirect even in the absence of any external bias. Significant densities of indirect excitons can accumulate in…
We demonstrate an electrostatic trap for indirect excitons in a field-effect structure based on coupled GaAs quantum wells. Within the plane of a double quantum well indirect excitons are trapped at the perimeter of a SiO2 area sandwiched…
We investigated excitonic absorptions in GaAs/AlAs/GaAs single barrier heterostructure using both photocapacitance and photocurrent spectroscopies at room temperature. Photocapacitance spectra show well defined resonance peak of indirect…
We show that a quasi-two dimensional condensate of optically active excitons emits coherent light even in the absence of population inversion. This allows an unambiguous and clear experimental detection of the condensed phase. We prove…
We describe the optical emission and the carrier dynamics of an ensemble of self-assembled GaAs quantum dots embedded in GaP(001). The QD formation is driven by the 3.6 % lattice mismatch between GaAs and GaP in Stranski-Krastanow mode…
The photoluminescence dynamics of a microscopic gas of indirect excitons trapped in coupled quantum wells is probed at very low bath temperature (approximately 350 mK). Our experiments reveal the non linear energy relaxation characteristics…
Excitons are spin integer particles that are predicted to condense into a coherent quantum state at sufficiently low temperature, and exciton condensates can be realized at much higher temperature than condensates of atoms because of strong…
We calculate the near-field optical spectra of excitons and biexcitons in semiconductor quantum dots naturally occurring at interface fluctuations in GaAs-based quantum wells, using a non-local description of the response function to a…
Indirect excitons -- pairs of electrons and holes spatially separated in semiconductor bilayers or quantum wells -- are known to undergo Bose-Einstein condensation and to form a quantum fluid. Here we show that this superfluid may…
We study the exciton gas-liquid transition in GaAs/AlGaAs coupled quantum wells. Below a critical temperature, Tc=4.8K, and above a threshold laser power density the system undergoes a phase transition into a liquid state. We determine the…