arXiv subjects

Xing-Yu Wang

Publications and source records attributed to Xing-Yu Wang.

7 recordsLinked to original sources

arXiv2026

Design A Family of 2D Nb-Based Multilayer Kagome Semimetals with High Fermi Velocity and Low Thermal Conductivity

Although two-dimensional (2D) multilayer kagome materials have opened up new windows of opportunity for exploring novel physical properties, their development has been constrained by the scarcity of available material systems. In light of this, in this study, relying on our previously proposed innovative "1+3" design strategy for multilayer kagome materials, we have successfully designed nine stable 2D niobium-based multilayer kagome monolayers with tunable compositions: Nb 6 Cl 2 S 3 Br 6 , Nb 6 Cl 2 S 4 Br 6 , Nb 6 Cl 2 Se 3 Br 6 , Nb 6 Cl 2 Se 4 Br 6 , Nb 6 Cl 2 S 1 Se 3 Br 6 , Nb 6 Cl 2 S 3 Se 1 Br 6 , Nb 6 S 4 Cl 8 , Nb 6 Se 4 Br 8 , and Nb 6 Br 2 S 3 Se 1 Cl 6 . These nine new materials all belong to the category of Dirac semimetals, with their Dirac cone structures primarily arising from the dz 2 orbitals based on Nb-based kagome lattice. Hybrid functional calculations reveal that these materials boast Fermi velocities as high as 2.36-3.04*10 5 m/s. Moreover, these materials generally exhibit characteristics of relatively low phonon group velocities and shorted phonon lifetimes. Under room temperature conditions, they possess comparatively low lattice thermal conductivities, with values ranging from 1.704-8.149 Wm -1 K -1 . Our research not only robustly confirms the feasibility of the "1+3" multilayer kagome lattices design strategy in the realm of kagome material development but also sets an exemplary benchmark for the study of Nb-based multilayer kagome materials.

cond-mat.mtrl-sci↗

arXiv2026

Designing a family of 2D kagome monolayer $B_{18}S_{8}$, $B_{18}S_{8}H_{2}$, $B_{18}S_{6}X_{2}$ (X=Cl,Br,I) with tunable Dirac cones and high Fermi velocity

Two-dimensional (2D) kagome materials have become a hot research topic in the current scientific community due to their unique electronic structural properties, and the design of novel 2D kagome materials represents a significant exploration direction in this field. In this study, by employing the "1+3" design strategy, surface passivation and charge balance strategies, we successfully designed a novel family of 2D kagome material $B_{18}S_{8}$, $B_{18}S_{8}H_{2}$, $B_{18}S_{6}X_{2}$ (X=Cl,Br,I). Electronic structure analysis revealed that although $B_{18}S_{8}$ exhibits excellent kagome band characteristics, its Dirac cone is located approximately 1 eV above the Fermi level, making it difficult to utilize. However, by surface hydrogen passivation, the Dirac cone can be effectively adjusted to the Fermi level. Further research found that introducing halogen atoms to replace surface sulfur atoms can similarly adjust the position of the Dirac cone to the Fermi level. The Fermi velocities near the Dirac cone for these five materials reach as high as 2.69 to 3.07*$10^5$ m/s. Additionally, spin-orbit coupling can open a bandgap of approximately 20 to 55 meV at the Dirac cone. Our research not only provides an outstanding example for the design of 2D boron-based kagome materials but also fully demonstrates the immense potential of such materials in the electronics field.

cond-mat.mtrl-sci↗

arXiv2026

Design of 2D V 6 S n Se 6-n Cl 6 (n=0, 2, 3, 5) with multilayer kagome lattice and ultrahigh electron mobility

Two-dimensional (2D) kagome materials have attracted considerable attention due to their unique electronic properties. Based on first-principles calculations and employing the "1+3" design strategy, we designed a class of composition-tunable 2D multilayer kagome materials, V 6 S n Se 6-n Cl 6 , and identified four stable structures: V 6 Se 6 Cl 6 , V 6 S 2 Se 4 Cl 6 , V 6 S 3 Se 3 Cl 6 , and V 6 S 5 Se 1 Cl 6 . 2D V 6 S n Se 6-n Cl 6 possesses three kagome layers, two of which are vanadium-based kagome layers, and the other is a sulfur or selenium atomic layer. Electronic structure analysis reveals that 2D V 6 S n Se 6-n Cl 6 is a narrow direct-bandgap semiconductor with a bandgap ranging from 0.568 to 0.742 eV, and exhibits ultrahigh electron mobility up to 4*10 4 cm 2 V -1 s -1 . Orbital analysis further demonstrates that the bands contributed by the V-based kagome layers form flat bands and Dirac cones below the Fermi level, and show a relatively high Fermi velocity. In summary, 2D V 6 S n Se 6-n Cl 6 provides an excellent platform for kagome physics research and the fabrication of nanoelectronic devices, adaptable to various device scenarios.

cond-mat.mtrl-sci↗

arXiv2025

Two-Dimensional Na2LiAlP2 Crystal for High-Performance Field-Effect Transistors

High-performance, low-power transistors are core components of advanced integrated circuits, and the ultimate limitation of Moore's law has made the search for new alternative pathways an urgent priority. Two-dimensional (2D) materials have become the most promising exploration target due to their exceptional electronic properties and scalability. In this work, we conducted device transport research on the previously proposed 2D quaternary semiconductor Na2LiAlP2 using the non-equilibrium Green's function method. The results demonstrate that even with a channel length of 5 nm, Na2LiAlP2 still exhibits excellent n-type transistor characteristics, fully meeting and surpassing the technical specifications outlined in the International Roadmap for Devices and Systems (IRDS). Encouragingly, the device can easily achieve the required on-state current of 900 {\mu}A/{\mu}m under low operating voltages of 0.1 V and 0.2 V. Moreover, at 0.1 V operating voltage, the device's subthreshold swing breaks through the theoretical limit of 60 mV/dec, reaching an astonishing value 30.33 mV/dec. Additionally, its p-type transistor performance also stands out with a subthreshold swing of ~50 mV/dec when the channel length is 7 nm. Our research not only showcases the exceptional transistor properties of Na2LiAlP2 but also further expands the research scope of 2D high-performance transistors.

cond-mat.mtrl-sci↗

arXiv2025

High-Throughput Screening of Transition Metal-Based 2D Multilayer Kagome Materials via the "1 + 3" Design Strategy

Two-dimensional (2D) kagome materials have drawn extensive research interest due to their unique electronic properties, like flat bands, magnetic frustration, and topological quantum states, which enable precise quantum state control and novel device innovation. Yet, simultaneously achieving high stability, tunability, and multifunctionality in 2D kagome systems remains a key material design challenge. In this study, we innovatively propose a new paradigm for constructing two-dimensional multi-kagome-layer materials based on the "1+3" design concept. By seamlessly integrating high-throughput screening techniques, we have successfully identified 6,379 novel 2D multilayer kagome candidates from a vast pool of candidates. These materials exhibit a rich diversity of types, encompassing 173 metals, 27 semimetals, 166 ferromagnetic semiconductors, and as many as 6,013 semiconductors. Furthermore, based on the 2D flat-band scoring criteria, we conducted a detailed analysis of the flat-band characteristics of the energy bands near the Fermi level in the predicted systems. Our findings reveal that approximately two-thirds of the systems meet the 2D flat-band scoring criteria, and notably, several systems exhibit nearly perfect flat-band characteristics. Our work provides an excellent paradigm for the design and research of 2D multilayer kagome materials

cond-mat.mtrl-sci↗

arXiv2025

A radiative neutrino mass model with leptoquarks under non-holomorphic modular $A_4$ symmetry

We investigate a radiative seesaw model with two leptoquarks under non-holomorphic modular $A_4$ symmetry. The leptons and quarks belong to non-trivial representations of the modular $A_4$ and the structures of their mass matrices are restricted. Neutrino masses are generated at one-loop level via leptoquark inside loop diagram where structures of relevant Yukawa interactions are determined by the modular $A_4$ symmetry. We scan the free parameters in the model and try to fit all the observed data for both lepton and quark sectors. For allowed parameters, we show some predictions regarding neutrino observables such as sum of neutrino mass and neutrinoless double beta decay.

hep-ph↗

arXiv2024

Leptonic dipole operator with $\Gamma_2$ modular invariance in light of Muon $(g-2)_\mu$

We have studied the leptonic EDM and the LFV decays relating with the recent data of anomalous magnetic moment of muon, $(g-2)_{\mu}$ in the leptonic dipole operator. We have adopted the successful $\Gamma_2$ modular invariant model by Meloni-Parriciatu as the flavor symmetry of leptons. Suppose the anomaly of $(g-2)_{\mu}$, $\Delta a_{\mu}$ to be evidence of New Physics (NP), we have related it with the anomalous magnetic moment of the electron $\Delta a_e$, the electron EDM $d_e$ and the $\mu\to e \gamma$ decay. We found that the NP contributions to $\Delta a_{e(\mu)}$ are proportional to the lepton masses squared likewise the naive scaling $\Delta a_\ell \propto m^2_\ell$. The experimental constraint of $|d_e|$ is much tight compared with the one from the branching ratio $\mathcal{B} (\mu \to e \gamma)$ in our framework. Supposing the phase of our model parameter $\delta_{\alpha}$ for the electron to be of order one, we have estimated the upper-bound of $\mathcal{B}(\mu \to e \gamma)$, which is at most $10^{-21}-10^{-20}$. If some model parameters are real, leptonic EDMs vanish since the CP phase of the modular form due to modulus $\tau$ does not contribute to the EDM. However, we can obtain $\mathcal{B} (\mu \to e \gamma)\simeq 10^{-13}$ with non-vanishing $d_e$ in a specific case. The imaginary part of a parameter can lead to $d_e$ in the next-to-leading contribution. The predicted electron EDM is below $10^{-32}$e\,cm, while $\mathcal{B} (\mu \to e \gamma)$ is close to the experimental upper-bound. The branching ratios of $\tau\to e\gamma$ and $\tau\to \mu\gamma$ are also discussed.

hep-ph↗