arXiv subjects

Xiaofeng Fan

Publications and source records attributed to Xiaofeng Fan.

10 recordsLinked to original sources

arXiv2026

Re-evaluation of bottleneck effect via a coupled monolayer WS_2/photonic crystal heterostructure

Exciton-polariton condensates is an important type of Bose-Einstein condensate whose realization requires efficient relaxation of polaritons to the band-energy minima. However, this process is often obstructed by bottleneck effect near the anticrossing region of polariton dispersion. Although the exciton-polariton bottleneck effect has been extensively observed in various polariton system, but there is no a unified views of physical origin. Here, we construct an exciton-trion-photon coupling system in monolayer WS_2/photonic-crystal slab heterostructures. Momentum-resolved photoluminescence reveals the anticrossing polariton dispersions for the exciton resonance with a ~57 meV Rabi splitting and there is no characteristic anticrossing for trion resonance with a ~5 meV splitting at ~12 K. Enhanced polariton emission is observed around the trion-polariton crossing with elevating temperature. We attributes this exotic phenomenon to bottleneck effect and indicating that small Rabi splitting is the unified origin of bottleneck effect in polariton systems.

physics.optics↗

arXiv2025

RIS-FUSION: Rethinking Text-Driven Infrared and Visible Image Fusion from the Perspective of Referring Image Segmentation

Text-driven infrared and visible image fusion has gained attention for enabling natural language to guide the fusion process. However, existing methods lack a goal-aligned task to supervise and evaluate how effectively the input text contributes to the fusion outcome. We observe that referring image segmentation (RIS) and text-driven fusion share a common objective: highlighting the object referred to by the text. Motivated by this, we propose RIS-FUSION, a cascaded framework that unifies fusion and RIS through joint optimization. At its core is the LangGatedFusion module, which injects textual features into the fusion backbone to enhance semantic alignment. To support multimodal referring image segmentation task, we introduce MM-RIS, a large-scale benchmark with 12.5k training and 3.5k testing triplets, each consisting of an infrared-visible image pair, a segmentation mask, and a referring expression. Extensive experiments show that RIS-FUSION achieves state-of-the-art performance, outperforming existing methods by over 11% in mIoU. Code and dataset will be released at https://github.com/SijuMa2003/RIS-FUSION.

cs.CV↗

arXiv2019

Structural Instability and Magnetism of Superconducting KCr$_3$As$_3$

We find a lattice instability in the superconductor KCr$_3$As$_3$, corresponding to a distortion of the Cr metallic wires in the crystal structure. This distortion couples strongly to both the electronic and magnetic properties, in particular by making the electronic structure much more nearly one-dimensional, and by shifting the compound away from magnetism. We discuss the implications of these results in the context of the possibly unconventional superconductivity of this phase.

cond-mat.supr-con↗

arXiv2017

Electronic fitness function for screening semiconductors as thermoelectric materials

We introduce a simple but efficient electronic fitness function (EFF) that describes the electronic aspect of the thermoelectric performance. This EFF finds materials that overcome the inverse relationship between $σ$ and $S$ based on the complexity of the electronic structures regardless of specific origin (e.g., isosurface corrugation, valley degeneracy, heavy-light bands mixture, valley anisotropy or reduced dimensionality). This function is well suited for application in high throughput screening. We applied this function to 75 different thermoelectric and potential thermoelectric materials including full- and half-Heuslers, binary semiconductors and Zintl phases. We find an efficient screening using this transport function. The EFF identifies known high performance $p$- and $n$-type Zintl phases and half-Heuslers. In addition, we find some previously unstudied phases with superior EFF.

cond-mat.mtrl-sci↗

arXiv2016

N-Type Oxide Thermoelectrics Via Visual Search Strategies

We discuss and present search strategies for finding new thermoelectric compositions based on first principles electronic structure and transport calculations. We illustrate them by application to a search for potential n-type oxide thermoelectric materials. This includes a screen based on visualization of electronic energy isosurfaces. We report compounds that show potential as thermoelectric materials along with detailed properties, including SrTiO3, which is a known thermoelectric, and appropriately doped KNbO3 and rutile TiO2.

cond-mat.mtrl-sci↗

arXiv2015

Nature of Valance Band Splitting on Multilayer MoS2

Understanding the origin of splitting of valance band is important since it governs the unique spin and valley physics in few-layer MoS2. With first principle methods, we explore the effects of spin-orbit coupling and layer's coupling on few-layer MoS2. It is found that intra-layer spin-orbit coupling has a major contribution to the splitting of valance band at K. In double-layer MoS2, the layer's coupling results in the widening of energy gap of splitted states induced by intra-layer spin-orbit coupling. The valance band splitting of bulk MoS_2 in K can follow this model. We also find the effect of inter-layer spin-orbit coupling in triple-layer MoS2. In addition, the inter-layer spin-orbit coupling is found to become to be stronger under the pressure and results in the decrease of main energy gap in the splitting valance bands at K.

cond-mat.mtrl-sci↗

arXiv2015

Magnetism in Na-filled Fe-based skutterudites

The interplay of superconductivity and magnetism is a subject of ongoing interest, stimulated most recently by the discovery of Fe-based superconductivity and the recognition that spin-fluctuations near a magnetic quantum critical point may provide an explanation for the superconductivity and the order parameter. Here we investigate magnetism in the Na filled Fe-based skutterudites using first principles calculations. NaFe4Sb12 is a known ferromagnet near a quantum critical point. We find a ferromagnetic metallic state for this compound driven by a Stoner type instability, consistent with prior work. In accord with prior work, the magnetization is overestimated, as expected for a material near an itinerant ferromagnetic quantum critical point. NaFe4P12 also shows a ferromagnetic instability at the density functional level, but this instability is much weaker than that of NaFe4Sb12, possibly placing it on the paramagnetic side of the quantum critical point. NaFe4As12 shows intermediate behavior. We also present results for skutterudite FeSb3, which is a metastable phase that has been reported in thin film form.

cond-mat.str-el↗

arXiv2014

Light scattering and surface plasmons on small spherical particles

Light scattering by small particles has a long and interesting history in physics. Nonetheless, it continues to surprise with new insights and applications. This includes new discoveries, such as novel plasmonic effects, as well as exciting theoretical and experimental developments such as optical trapping, anomalous light scattering, optical tweezers, nano-spasers, and novel aspects and realizations of Fano resonances. These have led to important new applications, including several ones in the biomedical area and in sensing techniques at the single-molecule level. There are additionally many potential future applications in optical devices and solar energy technologies. Here we review the fundamental aspects of light scattering by small spherical particles, emphasizing the phenomenological treatments and new developments in this field.

physics.optics↗

arXiv2010

Ultrafast carrier dynamics in pristine and FeCl3-intercalated bilayer graphene

Ultrafast carrier dynamics of pristine bilayer graphene (BLG) and bilayer graphene intercalated with FeCl3 (FeCl3-G), were studied using time-resolved transient differential reflection (delta R/R). Compared to BLG, the FeCl3-G data showed an opposite sign of delta R/R, a slower rise time, and a single (instead of double) exponential relaxation. We attribute these differences in dynamics to the down-shifting of the Fermi level in FeCl3-G, as well as the formation of numerous horizontal bands arising from the d-orbitals of Fe. Our work shows that intercalation can dramatically change the electronic structure of graphene, and its associated carrier dynamics.

cond-mat.mes-hall↗

arXiv2010

FeCl3 based Few-Layer Graphene Intercalation Compounds: Single Linear Dispersion Electronic Band Structure and Strong Charge Transfer Doping

Graphene has attracted great attentions since its first discovery in 2004. Various approaches have been proposed to control its physical and electronic properties. Here, we report that graphene based intercalation compounds is an efficient method to modify the electronic properties of few layer graphene (FLG). FeCl3 intercalated FLG were successfully prepared by two-zone vapor transport method. This is the first report on full intercalation for graphene samples. The features of the Raman G peak of such few-layer graphene intercalation compounds (FLGIC) are in good agreement with their full intercalation structures. The FLGIC presents single Lorentzian 2D peak, similar to that of single layer graphene, indicating the loss of electronic coupling between adjacent graphene layers. First principle calculations further reveal that the band structure of FLGIC is similar to single layer graphene but with strong doping effect due to the charge transfer from graphene to FeCl3. The successful fabrication of FLGIC opens a new way to modify properties of FLG for fundamental studies and future applications.

cond-mat.mtrl-sci↗