Superposition of intra- and inter-layer excitons in twistronic MoSe₂/WSe₂ bilayers probed by resonant Raman scattering

Abstract

Hybridisation of electronic bands of two-dimensional materials, assembled into twistronic heterostructures, enables one to tune their optoelectronic properties by selecting conditions for resonant interlayer hybridisation. Resonant interlayer hybridisation qualitatively modifies the excitons in such heterostructures, transforming these optically active modes into superposition states of interlayer and intralayer excitons. For MoSe2/WSe2 heterostructures, strong hybridization of both single particle and excitonic states can occur via single particle tunnelling. Here we use resonance Raman scattering to provide direct evidence for the hybridisation of excitons in twistronic MoSe2/WSe2 structures, by observing scattering of specific excitons by phonons in both WSe2 and MoSe2. We also demonstrate that resonance Raman scattering spectroscopy opens up a wide range of possibilities for quantifying the layer composition of the superposition states of the exciton and the interlayer hybridisation parameters in heterostructures of two-dimensional materials.

The sensitivity of magnetic particle imaging and fluorine-19 magnetic resonance imaging for cell tracking

“…In our experience, this can be reduced by mouse fasting, however, the amount of signal is unpredictable. Ultimately this background signal may obscure detection of cells, especially in low cell numbers 24 , as it is challenging (at this time, impossible) to distinguish the signal associated with cells from background. Second, there is some evidence that Brownian relaxation of SPION in different tissue environments may be altered, leading to reduced MPI sensitivity [25][26][27] .…”

In Vitro Degradation and Cytotoxicity of Eggshell-Based Hydroxyapatite: A Systematic Review and Meta-Analysis

“…The increasing soaking times in the in vitro degradation testing are directly linear to the degradation rate and weight loss of the materials [43]. As shown in Figure 5, the solutions used for in vitro degradation testing in the selected studies were phosphatebuffered saline (PBS) [27,33,35,43,49], Tris-buffered saline (TBS) [28][29][30][31], and simulated body fluid (SBF) [28,29]. The third solution has the same function with ion concentrations nearly equal to human blood plasma, according to the conditions in the human body.…”

“…Weight loss that is too high causes the pH to be high as well, thus limiting clinical applications [28]. It is necessary to add other elements that are safe for medical applications to stabilize the weight loss of hydroxyapatite-wollastonite composites, including zirconia (Zr) [31] and argentum (Ag) [30], as well as the selection of the solutions used [35]. With the same soaking time and solution, zirconia is able to reduce the weight loss of materials.…”

“…Out of 71 relevant article titles collected from SCOPUS, PubMed, and Google Scholar, only 36 were included after screening the title, abstract, and content for in vitro degradation and cytotoxicity testing for the biocompatibility of eggshell-based hydroxyapatite. The articles came from several countries, such as India [11,14,[27][28][29][30][31][32][33][34][35][36][37][38][39][40], Bangladesh [41,42], China [43], Korea [25,44,45], Turkey [46][47][48], Thailand [49,50], Brazil [26], Italy [51], USA [52], Romania [2], Vietnam [53,54], Colombia [55], and Egypt [56]. The study selection of the articles included in the systematic review is shown in Figure 1.…”

“…Weight loss analysis is affected by the number of days and solutions used during the soaking process, along with the composition of the material. Weight loss can also be observed by the purity and shape of the hydroxyapatite powder, microstructure of hydroxyapatite [31], the condition of the human body, or the solutions used to adjust to the pH of the human body [27]. The observed porosity of the microstructure hydroxyapatite affects the absorption of the solution used due to the surface area of eggshell-based hydroxyapatite [27].…”