Related papers: Control of excitonic absorption by thickness varia…
We present an electrostatic theory of band gap renormalization in atomically-thin semiconductors that captures the strong sensitivity to the surrounding dielectric environment. In particular, our theory aims to correct known band gaps, such…
Topological insulator films are promising materials for optoelectronics due to a strong optical absorption and a thickness dependent band gap of the topological surface states. They are superior candidates for photodetector applications in…
Periodic metallic gratings on substrates can support a range of electromagnetic modes, such as leaky waveguide, guided-resonant, and Fabry-Perot (FP) cavity modes, which can strongly modulate optical transmission under resonant excitation.…
We demonstrate a graphene-based Salisbury screen consisting of a single layer of graphene placed in close proximity to a gold back reflector. The light absorption in the screen can be actively tuned by electrically gating the carrier…
In this study, the optical response to a terahertz pulse was investigated in the transition metal chalcogenide Ta$_2$NiSe$_5$, a candidate excitonic insulator. First, by irradiating a terahertz pulse with a relatively weak electric field…
It is well-known that exciton effects are determinant to understand the optical absorption spectrum of low-dimensional materials. However, the role of excitons in nonlinear optical responses has been much less investigated at an…
Understanding and controlling the nanoscale transport of excitonic quasiparticles in atomically thin 2D semiconductors is crucial to produce highly efficient nano-excitonic devices. Here, we present a nano-gap device to selectively confine…
Ballistic semiconductor structures have allowed the realization of optics-like phenomena in electronics, including magnetic focusing and lensing. An extension that appears unique to graphene is to use both n and p carrier types to create…
Recent realizations of exotic topological states in condensed matter and cold atoms have advanced the exploration for topological characteristics, such as invariant topological orders and band inversion. Here we construct a 1D optical…
The discovery of correlated phases in twisted moir\'e superlattices accelerated the search for low-dimensional materials with exotic properties. A promising approach uses engineered substrates to strain the material. However, designing…
Even the best quality 2D materials have non-negligible concentrations of vacancies and impurities. It is critical to understand and quantify how defects change intrinsic properties, and use this knowledge to generate functionality. This…
We theoretically study dynamical excitonic condensates occurring in bilayers with an imposed chemical potential difference and in photodoped semiconductors. We show that optical spectroscopy can experimentally identify phase-trapped and…
The magneto-optical response of monolayer transition metal dichalcogenides (TMDs), including excitonic effects, is studied using a nanoribbon geometry. We compute the diagonal optical conductivity and the Hall conductivity. Comparing the…
Two-dimensional (2d) nano-electronics, plasmonics, and emergent phases require clean and local charge control, calling for layered, crystalline acceptors or donors. Our Raman, photovoltage, and electrical conductance measurements combined…
Through systematic experimental and theoretical studies of layer-thickness-dependent absorption in semiconducting MoSe$_2$ and WS$_2$ across the visible to near-infrared spectral range, we demonstrate a universal absorption behavior in…
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 introduce a new technique to probe the properties of an interacting cold atomic gas that can be viewed as a dynamical compressibility measurement. We apply this technique to the study of the superfluid to Mott insulator quantum phase…
In this letter, we report the first observation of dramatic decrease in nanosecond (ns) pulsed laser induced transient absorption (TA) in a-GexAs35-xSe65 thin films by tuning the amorphous network from floppy to rigid. Our results provide…
Electromagnetic waves propagating in a layered superconductor with arbitrary momentum with respect to the main crystallographic directions display an unavoidable mixing between longitudinal and transverse degrees of freedom. Here we show…
Emerging photo-induced excitonic processes in transition metal dichalcogenide (TMD) heterobilayers, e.g., coupling, dephasing, and energy transfer of intra- and inter-layer excitons, allow new opportunities for ultrathin photonic devices.…