Related papers: Excitons in WSe2 time-resolved ARPES: particle or …
Understanding collective electronic states such as superconductivity and charge density waves is pivotal for fundamental science and applications. The layered transition metal dichalcogenide 1T-TiSe2 hosts a unique charge density wave (CDW)…
The optical properties of monolayer transition metal dichalcogenides are dominated by tightly-bound excitons. They form at distinct valleys in reciprocal space, and can interact via the valley-exchange coupling, modifying their dispersion…
Bulk layered MX2 transition metal chalcogenides (M = Mo, W and X = S, Se) are known to exhibit an indirect to direct band gap transition as the number of layers is reduced. Previous time-resolved work has principally focused on the…
Recent experiments suggest that excitonic degrees of freedom play an important role in precipitating the charge density wave (CDW) transition in $1T$-$\mathrm{TiSe}_2$. Through systematic calculations of the electronic and phonon spectrum…
Excitons -- bound electron-hole pairs -- play a central role in light-matter interaction phenomena, and are crucial for wide-ranging applications from light harvesting and generation to quantum information processing. A long-standing…
Manipulation of intrinsic electron degrees of freedom, such as charge and spin, gives rise to electronics and spintronics, respectively. Electrons in monolayer materials with a honeycomb lattice structure, such as the Transition-Metal…
Atomically thin layer transition metal dichalcogenides have been intensively investigated for their rich optical properties and potential applications in nano-electronics. In this work, we study the incoherent optical phonon and exciton…
Semiconducting transition metal dichalcogenide monolayers have emerged as promising candidates for future valleytronics-based quantum information technologies. Two distinct momentum-states of tightly-bound electron-hole pairs in these…
The optical selection rules for inter-band transitions in WSe2, WS2 and MoSe2 transition metal dichalcogenide monolayers are investigated by polarization-resolved photoluminescence experiments with a signal collection from the sample edge.…
We report on the direct mapping of electron transfer in the momentum space of bulk MoS$_2$ by means of time- and angle-resolved two-photon photoemission with a high-harmonic probe. For this purpose, we have combined a high-repetition rate…
The semiconductor ReSe$_2$ is characterized by a strongly anisotropic optical absorption and is therefore promising as an optically active component in two-dimensional heterostructures. However, the underlying femtosecond dynamics of…
The optical properties of transition metal dichalcogenide monolayers such as the two-dimensional semiconductors MoS$_2$ and WSe$_2$ are dominated by excitons, Coulomb bound electron-hole pairs. The light emission yield depends on whether…
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…
Strong Coulomb interactions in two-dimensional (2D) semiconductors give rise to tightly bound excitons, exciton polarons, and correlated electronic phases such as Wigner crystals (WCs), yet their mutual interplay remains poorly understood.…
Angle-resolved photoemission spectra of alkali metals exhibit a puzzling, non-dispersing peak in the apparent density of states near the Fermi energy. We argue that the holes left behind a significant fraction of photoejected electrons are…
Coherent excitation of materials via ultrafast laser pulses can have interesting, observable dynamics in time-resolved photoemission measurements. The broad spectral width of ultrafast pump pulses can coherently excite multiple exciton…
Transition metal dichalcogenides (TMDCs) heterostructure with a type II alignment hosts unique interlayer excitons with the possibility of spin-triplet and spin-singlet states. However, the associated spectroscopy signatures remain elusive,…
In this paper, we have developed a theory describing surface exciton polariton (SEPs) that accounts for the spatial dispersion of the dielectric constant connected with exciton momentum. Due to strong coupling between light and bulk…
We discuss, from a theoretical point of view, excitonic phases at the pressure induced semiconductor-semimetal transition in $\rm TmSe_{0.45}Te_{0.55}$,focusing, in particular, on the stability against an electron-hole liquid. The…
Spontaneous symmetry breaking, arising from the competition of interactions and quantum fluctuations, is fundamental to understanding ordered electronic phases. Although electrically neutral, optical excitations like excitons can interact…