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Jingyu Yao

Publications and source records attributed to Jingyu Yao.

6 recordsLinked to original sources

BotzoneBench: Scalable LLM Evaluation via Graded AI Anchors

Large Language Models (LLMs) are increasingly deployed in interactive environments requiring strategic decision-making, yet systematic evaluation of these capabilities remains challenging. Existing benchmarks for LLMs primarily assess static reasoning through isolated tasks and fail to capture dynamic strategic abilities. Recent game-based evaluations employ LLM-vs-LLM tournaments that produce relative rankings dependent on transient model pools, incurring quadratic computational costs and lacking stable performance anchors for longitudinal tracking. The central challenge is establishing a scalable evaluation framework that measures LLM strategic reasoning against consistent, interpretable standards rather than volatile peer models. Here we show that anchoring LLM evaluation to fixed hierarchies of skill-calibrated game Artificial Intelligence (AI) enables linear-time absolute skill measurement with stable cross-temporal interpretability. Built on the Botzone platform's established competitive infrastructure, our BotzoneBench evaluates LLMs across eight diverse games spanning deterministic perfect-information board games to stochastic imperfect-information card games. Through systematic assessment of 177,047 state-action pairs from five flagship models, we reveal significant performance disparities and identify distinct strategic behaviors, with top-performing models achieving proficiency comparable to mid-to-high-tier specialized game AI in multiple domains. This anchored evaluation paradigm generalizes beyond games to any domain with well-defined skill hierarchies, establishing a scalable and reusable framework for assessing interactive AI capabilities.

cs.AI

Spin-polarized triplet excitonic insulators in Ta3X8 (X=I, Br) monolayers

Bose-Einstein condensation of spin-polarized triplet excitons can give rise to an intriguing spin supercurrent, enabling experimental detection of exciton condensation. In this work, we predict that Ta3X8 (X=I, Br) ferromagnetic monolayers are spin-polarized triplet excitonic insulators (EIs), based on the systematic first-principles GW calculations coupled with the Bethe-Salpeter equation (GW+BSE). The single-particle calculations of spin-polarized band structures reveal that these monolayers are bipolar magnetic semiconductors, where the highest valence band and the lowest conduction band possess opposite spin polarization. The two low-energy bands, primarily originating from Ta $d_{z^2}$ orbitals, are almost flat. The same-orbital parity and opposite-spin natures of the band-edge states effectively suppress dielectric screening, promoting the emergence of the EI state. The GW+BSE calculations reveal that the binding energy of the lowest-energy exciton is 1.499 eV for Ta3I8 monolayer and 1.986 eV for Ta3Br8 monolayer. Since both values exceed the respective GW band gaps, these results indicate a strong excitonic instability in these monolayers. A wavefunction analysis confirms that the lowest-energy exciton is a tightly bound Frenkel-like state, exhibiting a spin-polarized triplet nature with $S_z=1$. Our findings establish a valuable material platform for investigating spin-polarized triplet EIs, offering promising potential for spintronic applications.

cond-mat.mtrl-sci

Axion insulator, Weyl points, quantum anomalous Hall effect and magnetic topological phase transition in Eu3In2As4

The magnetic topological phases attract much interest, such as the axion insulator, higher-order topology, Weyl semimetals, and the quantum anomalous Hall effect (QAHE). Here, we predict that the axion insulator phase, magnetic Weyl points, and QAHE can be achieved in Eu3In2As4. Recently, the single-crystal Eu3In2As4 has been successfully synthesized, which exhibits an antiferromagnetic (AFM) ground state. Our first-principles calculations show that it lies on the phase boundary between multiple magnetic topological phases, and the magnetic anisotropy is weak, with an energy difference less than 1 meV. In the AFM state, it can be tuned to an axion insulator by tensile strain. The quantized axion angle $θ= π$ and the magnetic higher-order topology are characterized by the parity index $Z_4 = 2$. By applying an external magnetic field, the induced ferromagnetic (FM) state becomes an ideal magnetic topological semimetal with a single pair of Weyl points or a nodal ring. The QAHE can be achieved in FM multilayer films of Eu3In2As4 on a magnetic insulating substrate.

cond-mat.mtrl-sci

Excitonic Instability in Ta2Pd3Te5 Monolayer

By systematic theoretical calculations, we have revealed an excitonic insulator (EI) in the Ta2Pd3Te5 monolayer. The bulk Ta2Pd3Te5 is a van der Waals (vdW) layered compound, whereas the vdW layer can be obtained through exfoliation or molecular-beam epitaxy. First-principles calculations show that the monolayer is a nearly zero-gap semiconductor with the modified Becke-Johnson functional. Due to the same symmetry of the band-edge states, the two-dimensional polarization $α_{2D}$ would be finite as the band gap goes to zero, allowing for an EI state in the compound. Using the first-principles many-body perturbation theory, the GW plus Bethe-Salpeter equation calculation reveals that the exciton binding energy is larger than the single-particle band gap, indicating the excitonic instability. The computed phonon spectrum suggests that the monolayer is dynamically stable without lattice distortion. Our findings suggest that the Ta2Pd3Te5 monolayer is an excitonic insulator without structural distortion.

cond-mat.mtrl-sci

Evidence for an Excitonic Insulator State in Ta$_2$Pd$_3$Te$_5$

The excitonic insulator (EI) is an exotic ground state of narrow-gap semiconductors and semimetals arising from spontaneous condensation of electron-hole pairs bound by attractive Coulomb interaction. Despite research on EIs dating back to half a century ago, their existence in real materials remains a subject of ongoing debate. In this study, through systematic experimental and theoretical investigations, we provide evidence for the existence of an EI ground state in a van der Waals compound Ta$_2$Pd$_3$Te$_5$. Density-functional-theory calculations suggest that it is a semimetal with a small band overlap, whereas various experiments exhibit an insulating ground state with a clear band gap. Upon incorporating electron-hole Coulomb interaction into our calculations, we obtain an EI phase where the electronic symmetry breaking opens a many-body gap. Angle-resolved photoemission spectroscopy measurements exhibit that the band gap is closed with a significant change in the dispersions as the number of thermally excited charge carriers becomes sufficiently large in both equilibrium and nonequilibrium states. Structural measurements reveal a slight breaking of crystal symmetry with exceptionally small lattice distortion in the insulating state, which cannot account for the significant gap opening. Therefore, we attribute the insulating ground state with a gap opening in Ta$_2$Pd$_3$Te$_5$ to exciton condensation, where the coupling to the symmetry-breaking electronic state induces a subtle change in the crystal structure.

cond-mat.mtrl-sci

Discovery of a Magnetic Topological Semimetal Eu$_3$In$_2$As$_4$ with a Single Pair of Weyl Points

Magnetic Weyl semimetal (MWS) is a unique topological state with open surface Fermi arc states and other exotic transport phenomena. However, most reported MWSs show multiple pairs of Weyl points and complicated Fermi surfaces, which increases the difficulty of the investigation into the intrinsic chiral transport property. In this wor, we successfully synthesized a soft magnetic Weyl semimetal Eu$_3$In$_2$As$_4$ with a single pair of Weyl points under magnetic fields. The Shubnikov de Haas (SdH) oscillation with a single frequency, as well as a linear hall resistance with the same carrier density, is observed up to 50 Tesla, indicating a single pair of Weyl points around the Fermi level with a massless fermion ($m^* = 0.121 m_0$, $π$ Berry phase). Such a single pair of Weyl points is further confirmed by the density functional theory calculations. The magnetic ordering and band topology can be easily tuned by the external magnetic field. The field-induced MWS Eu$_3$In$_2$As$_4$ with a single pair of Weyl points is a good platform to detect chiral transport properties, including possible quantum anomalous Hall effect.

cond-mat.mes-hall