RESUMEN
This study investigates the scope of application of a recently designed inversion methodology that is capable of obtaining structural information about disordered systems through the analysis of their conductivity response signals. Here we demonstrate that inversion tools of this type are capable of sensing the presence of disorderly distributed defects and impurities even in the case where the scattering properties of the device are only weakly affected. This is done by inverting the DC conductivity response of monolayered MoS2films containing a minute amount of AuCl3coordinated complexes. Remarkably, we have successfully extracted detailed information about the concentration of AuCl3by decoding its signatures on the transport features of simulated devices. In addition to the case of theoretically generated Hamiltonians, we have also carried out a full inversion procedure from experimentally measured signals of similar structures. Based on experimental input signals of MoS2with naturally occurring vacancies, we were able to quantify the vacancy concentration contained in the samples, which indicates that the inversion methodology has experimental applicability as long as the input signal is able to resolve the characteristic contributions of the type of disorder in question. Being able to handle more complex, realistic scenarios unlocks the method's applicability for designing and engineering even more elaborate materials.
RESUMEN
Epsilon near-zero photonics and surface polariton nanophotonics have become major fields within optics, leading to unusual and enhanced light-matter interaction. Specific dielectric responses are required in both cases, which can be achieved, e.g., via operation near a material's electronic or phononic resonance. However, this condition restricts operation to a specific, narrow frequency range. It has been shown that using a thin dielectric layer can adjust the dielectric response of a surface and, therefore, the operating frequency for achieving specific photonic excitations. Here, we show that a surface's optical properties can be tuned via the deposition/transference of ultra-thin layered van der Waals (vdW) crystals, the thicknesses of which can easily be adjusted to provide the desired response. In particular, we experimentally and theoretically show that the surface phonon resonance of a silica surface can be tuned by â¼50 cm-1 through the simple deposition of nanometer-thick exfoliated flakes of black phosphorus. The surface properties were probed by infrared nanospectroscopy, and results show a close agreement with the theory. The black phosphorus-silica layered structure effectively acts as a surface with a tunable effective dielectric constant that presents an infrared response dependent on the black phosphorus thickness. In contrast, with a lower dielectric constant, hexagonal boron nitride does not significantly tune the silica surface phonon polariton. Our approach also applies to epsilon near-zero surfaces, as theoretically shown, and to polaritonic surfaces operating at other optical ranges.