Related papers: Giant excitonic effects in bulk vacancy-ordered do…
We have accurately determined the exciton binding energy and reduced mass of single crystals of methylammonium lead tri-iodide using magneto-reflectivity at very high magnetic fields. The single crystal has excellent optical properties with…
The existence of strongly bound excitons is one of the hallmarks of the newly discovered atomically thin semi-conductors. While it is understood that the large binding energy is mainly due to the weak dielectric screening in two dimensions…
Vacancy ordered halide perovskites have been extensively investigated as promising lead-free alternatives to halide perovskites for various opto-electronic applications. Among these Cs$_{2}$TiBr$_{6}$ has been reported as a stable absorber…
We have revisited Cooper's one pair problem of calculating the binding energy for two electrons, experiencing an attractive interaction near the Fermi surface, in case of quasi one dimensional lattice system. Though it is a generalized…
Exciton problem is solved in the two-dimensional Dirac model with allowance for strong electron-hole attraction. The exciton binding energy is assumed smaller than but comparable to the band gap. The exciton wavefunction is found in the…
Bound electron-hole pairs in semiconductors known as excitons are the subject of intense research due to their potential for optoelectronic devices and applications, especially in the realm of two-dimensional materials. While the properties…
Excitons -- two-particle correlated electron-hole pairs -- are the dominant low-energy optical excitation in the broad class of semiconductor materials, which range from classical silicon to perovskites, and from two-dimensional to organic…
Excitons play major roles in optical processes in modern semiconductors, such as single-wall carbon nanotubes (SWCNTs), transition metal dichalcogenides, and 2D perovskite quantum wells. They possess extremely large binding energies…
The perovskite-inspired bismuth halide semiconductor Cs3Bi2Br9 is widely investigated as photoactive material for light-conversion applications. However, charge generation and separation are inherently limited by its modest sunlight…
Excitons dominate the optics of atomically-thin transition metal dichalcogenides and 2D van der Waals heterostructures. Interlayer 2D excitons, with an electron and a hole residing in different layers, form rapidly in heterostructures…
An excitonic insulator phase is expected to arise from the spontaneous formation of electron-hole pairs (excitons) in semiconductors where the exciton binding energy exceeds the size of the electronic band gap. At low temperature, these…
We report the band structures and excitonic properties of delafossites $CuMO_2$ (M = Al, Ga, In, Sc, Y, Cr) calculated using the state-of-the-art $\textit{GW}$-BSE approach. We find that all the delafossites are indirect band gap…
New blends of simply synthesized quasi two-dimensional (quasi-2D) hydrophobic perovskite semiconductors, employed in high performance light emitting diodes (LEDs) which function due to excitonic energy transfer effects, are reported. These…
Harnessing the optoelectronic response of organic semiconductors requires a thorough understanding of the fundamental light-matter interaction that is dominated by the excitation of correlated electron-hole pairs, i.e. excitons. The nature…
We discuss neutral and charged complexes (biexciton and trion) formed by indirect excitons in layered quasi-two-dimensional semiconductor heterostructures. Indirect excitons -- long-lived neutral Coulomb-bound pairs of electrons and holes…
In two-dimensional hybrid organic-inorganic metal-halide perovskites, the intrinsic optical lineshape reflects multiple excitons with distinct binding energies, each dressed differently by the hybrid lattice. Given this complexity, a…
We report on small-cluster exact-diagonalization calculations which prove the formation of electron-hole pairs (excitons) as prerequisite for spontaneous interlayer phase coherence in bilayer systems described by the extended…
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…
The opening of an energy gap in the electronic structure generally indicates the presence of interactions. In materials with low carrier density and short screening length, long-range Coulomb interaction favors the spontaneous formation of…
We present a many-body calculation of the band structure and optical spectrum of the layered hybrid organic-inorganic halide perovskites in the Ruddlesden-Popper phase with the general formula A$^{'}_{2}$A$_{n-1}$M$_{n}$X$_{3n+1}$, focusing…