Related papers: Interseries transitions between Rydberg excitons i…
The optical dielectric function of ZnGeN$_2$ is calculated from the interband transitions using the energy bands calculated in the quasiparticle self-consistent (QS)$G\hat W$ method using two different levels of approximation: the…
The interplay of nearly degenerate orders in quantum materials can lead to a myriad of emergent phases. A prominent case is that of the high-Tc cuprates for which the relationship between superconductivity and a short-ranged, incommensurate…
Cascade transition between energy levels has important applications, such as in quantum information protocols and quantum cascade lasers. In two-dimensional heterostructure, the moir\'e superlattice potential can result in multiple…
We present the analytical method enables one to compute the optical functions i.e., reflectivity, transmission and absorption including the excitonic effects for a semiconductor crystal exposed to a uniform electric field for energy region…
Atomically thin two-dimensional crystals have revolutionized materials science. In particular, monolayer transition metal dichalcogenides promise novel optoelectronic applications, due to their direct energy gaps in the optical range. Their…
We report the observation of dipole-forbidden, but quadrupole-allowed, one-photon transitions to high Rydberg states in Rb. Using pulsed UV excitation of ultracold atoms in a magneto-optical trap, we excite $5s \to nd$ transitions over a…
Electron irradiation has been used to introduce point defects in a controlled way in the CuO2 planes of underdoped and optimally doped YBCO. This technique allows us to perform very accurate measurements of Tc and of the residual…
The recent observation of high-lying Rydberg states of excitons in semiconductors with relatively high binding energy motivates exploring their applications in quantum nonlinear optics and quantum information processing. Here, we study…
Excitons, electron-hole pairs bound by the Coulomb potential, are fundamental quasiparticles of coherent light-matter interaction energizing processes from photosynthesis to optoelectronics. Excitons are observed in semiconductors, and…
Recently, we have derived the changes in the absorption spectrum of an exciton when this exciton is photocreated close to a metal. The resolution of this problem -- which has similarities with Fermi edge singularities -- has been made…
We analyze how the coherence peaks observed in Scanning Tunneling Spectroscopy (STS) of cuprate high temperature superconductors are transferred from the cuprate layer to the oxide layers adjacent to the STS microscope tip. For this…
We calculate collision strengths and their thermally-averaged Maxwellian values for electron excitation and de-excitation between the fifteen lowest levels of singly-ionised cobalt, Co+, which give rise to emission lines in the near- and…
Rydberg states of excitons in Cu$_2$O are known to interact strongly with other carriers in their surrounding such as other excitons, free charge carriers and static charged impurities. In cw-experiments, discriminating the individual…
Electronic functionalities in materials from silicon to transition metal oxides are to a large extent controlled by defects and their relative arrangement. Outstanding examples are the oxides of copper, where defect order is correlated with…
Localized $5d^2$ electrons in a cubic crystal field possess multipoles such as electric quadrupoles and magnetic octupoles. We studied the cubic double perovskite Ba$_2$CaOsO$_6$ containing the Os$^{6+}$ ($5d^2$) ions, which exhibits a…
Photoluminescence excitation spectroscopy has revealed a novel, highly efficient two-photon excitation method to produce a cold, uniformly distributed high density excitonic gas in bulk cuprous oxide. A study of the time evolution of the…
We study the convergence of bound-state quadrupole moments in finite harmonic oscillator spaces. We derive an expression for the infrared extrapolation for the quadrupole moment of a nucleus and benchmark our results using different model…
Complexity in many-particle systems occurs through processes of qualitative differentiation. These are described by concepts such as emerging states with specific symmetries that are linked to order parameters. In quantum Hall phases of…
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…
Defects in cuprous oxide (Cu$_2$O) strongly influence its performance in applications ranging from photovoltaics to emerging quantum technologies based on Rydberg excitons where microscopic crystal purity is essential. Photoluminescence…