arXiv subjects

Nan Pan

Publications and source records attributed to Nan Pan.

4 recordsLinked to original sources

arXiv2023

Predicting RNA-small molecule binding sites by 3D structure

The prediction of RNA-small molecule binding sites is crucial for the discovery of effective drugs. Various computational methods have been developed to address this challenge, using information about the structure and sequence of RNA. In this study, we introduce CplxCavity, a combination of a new algorithm and a machine learning model specifically designed to predict RNA-small molecule binding sites. CplxCavity leverages the 3D structure of RNA or RNA complexes to identify surface cavities that have the potential to bind with small molecules. Our results demonstrate that CplxCavity outperforms existing methods by accurately identifying binding sites for small molecules on RNA or RNA complexes. The introduction of CplxCavity represents a significant advancement in computational tools for studying RNA-ligand interactions, and offers promising prospects for accelerating drug discovery and the development of therapies targeting RNA.

q-bio.QM↗

arXiv2023

Interlayer donor-acceptor pair excitons in MoSe2/WSe2 moir\'e heterobilayer

Localized interlayer excitons (LIXs) in two-dimensional moir\'e superlattices exhibit sharp and dense emission peaks, making them promising as highly tunable single-photon sources. However, the fundamental nature of these LIXs is still elusive. Here, we show the donor-acceptor pair (DAP) mechanism as one of the origins of these excitonic peaks. Numerical simulation results of the DAP model agree with the experimental photoluminescence spectra of LIX in the moir\'e MoSe2/WSe2 heterobilayer. In particular, we find that the emission energy-lifetime correlation and the nonmonotonic power dependence of the lifetime agree well with the DAP IX model. Our results provide insight into the physical mechanism of LIX formation in moir\'e heterostructures and pave new directions for engineering interlayer exciton properties in moir\'e superlattices.

cond-mat.mes-hall↗

arXiv2019

Magnetically-Sensitive Valley Polarization Reversal and Revival of Defect-Localized Excitons in WSe2-WS2

Manipulating and reserving the valley pseudospin of excitons is one core aim in the two-dimensional transition metal dichalcogenides (TMDs). However, due to the strong electron-hole exchange and spin-orbit coupling interactions, the exciton recombination lifetime is subject to picosecond timescale intrinsically, and the valley polarization is hardly modulated by a moderate magnetic field. It is fortunate that interlayer and defect-localized excitons promise to overcome these difficulties by suppressing the above interactions. Here we clearly reveal that the valley polarization can be reversed and revived in the defect-localized excitons with a microsecond lifetime in AB-stacked WSe2-WS2 heterobilayer. Specifically, for the interlayer defect-localized exciton, the valley polarization is reversed and can be efficiently enhanced by a weak out-of-plane magnetic field (<0.4 T). In sharp contrast, the valley polarization of the intralayer defect-localized exciton can revive after a fast decay process and follows the direction of the moderate out-of-plane magnetic field (<3 T). We explain the reversed valley polarization with highly magnetic sensitivity by the delocalization of defect-localized holes under a weak magnetic field and the revival of valley polarization by the valley Zeeman effect under a moderate magnetic field. Our results demonstrate that the valley pseudospin of defect-localized excitons can be efficiently modulated by the external magnetic field and enrich both the understanding and the technical approaches on manipulating the valley dynamics in TMDs and their heterostructure.

cond-mat.mtrl-sci↗

arXiv2018

Edge optical scattering of two-dimensional materials

Rayleigh scattering has shown powerful abilities to study electron resonances of nanomaterials regardless of the specific shapes. In analogy to Rayleigh scattering, here we demonstrate that edge optical scattering from two-dimensional (2D) materials also has the similar advantage. Our result shows that, in visible spectral range, as long as the lateral size of a 2D sample is larger than 2 μm, its edge scattering is essentially a knife-edge diffraction, and the intensity distribution of the high-angle scattering in $\mathbf{k}$ space is nearly independent of the lateral size and the shape of the 2D samples. The high-angle edge scattering spectra are purely determined by the intrinsic dielectric properties of the 2D materials. As an example, we experimentally verify this feature in single-layer $MoS_{2}$, in which A and B excitons are clearly detected in the edge scattering spectra, and the scattering images in $\mathbf{k}$ space and real space are consistent with our theoretical model. This study shows that the edge scattering is a highly practical and efficient method for optical studies of various 2D materials as well as thin films with clear edges.

cond-mat.mes-hall↗