Kagome magnets exhibit a range of novel and nontrivial topological properties due to the strong interplay between topology and magnetism, which also extends to their thermoelectric applications. Recent advances in the study of magnetic topological materials have highlighted their intriguing anomalous Hall and thermoelectric effects, arising primarily from large intrinsic Berry curvature. Here, we report observation of a large room-temperature (RT) anomalous Nernst effects (ANE) of S x y A $S_{xy}^A$ ∼ 1.3 µV K-1 in the kagome antiferromagnet (AFM) ErMn6Sn6, which is comparable to the largest signals observed in known magnetic materials. Surprisingly, we further found that a significant topological Nernst signal at RT and peaking a maximum of approximately 0.2 µV K-1 at 180 K, exactly coupling with ANE in the spiral AFM state, originates from the real-space nonzero spin chirality caused by incommensurate spin structure. This study demonstrates a potential room-temperature thermoelectric application platform based on the Nernst effect, and provides insights for discovering significant anomalous and topological transverse transport effects in the Incommensurate spin texture, Kagome antiferromagnet, Thermoelectric effect, Topological Nernst effectincommensurate AFM system.

We report the discovery of bulk superconductivity in a new quinary intermetallic compound Th 2 Mo 2 Ru 2 Si 4 C, which crystallizes in a collapsed 22241-type structure. This structure is characterized as an intergrowth of ThMo 2 Si 2 C and ThRu 2 Si 2 units, interconnected by equivalent Si-Si bondings that enhance inter-sublattice coupling. The refined lattice parameters are a = 4.2212(1) Å and c = 20.3899(7) Å. Electrical resistivity and magnetic susceptibility measurements on both polycrystalline and single-crystal samples consistently demonstrate bulk superconductivity with a transition temperature T c ~6.0 K, significantly higher than those of the constituent compound ThMo 2 Si 2 C and related analogs. The superconducting state exhibits nearly isotropic behavior under magnetic fields, attributable to strong covalent interlayer coupling. First-principles calculations reveal a substantial contribution from Mo- d orbitals near the Fermi level, which exhibits several band crossing points. The enhancement in T c can be explained by a synergistic combination of a valence electron concentration and an inter-sublattice self-doping effect between the [Ru 2 Si 2 ] and [Mo 2 Si 2 C] layers.

Ising spin-orbit coupling in bulk systems has drawn considerable interest for its ability to conveniently construct spin-orbit environments and enable exotic quantum phenomena. In this work, we synthesize intercalated 2Hb-TaSe_2 bilayers with noncentrosymmetric structure and, through multifaceted analysis, present multiple lines of evidence for the emergence of bulk Ising superconductivity. Resistivity measurements reveal anisotropic superconducting behavior, with a remarkably large in-plane upper critical field B_c2^ that exceeds the Pauli limit B_p. Band structure calculations further show band splitting accompanied by out-of-plane spin polarization. Collectively, these observations point to the presence of Ising superconductivity. Additional measurements of the thickness-dependent ratio B_c2^/B_p and the superconducting diode effect not only further support the Ising superconducting nature of this material, but also reveal additional features of bulk Ising superconductivity evolving with thickness. Our findings provide valuable insights that may contribute to the search for bulk Ising superconductors.

We report the discovery of bulk superconductivity in a new quinary intermetallic compound Th2Mo2Ru2Si4C, crystallized in a collapsed 22241-type structure. This structure is characterized by the intergrowth of ThMo2Si2C and ThRu2Si2 units interconnected by equivalent Si-Si bonds that enhance inter-sublattice coupling. The refined lattice parameters are a = 4.2212(1) & Aring; and c = 20.3899(7) & Aring;. Electrical resistivity and magnetic susceptibility measurements of both polycrystalline and single-crystal samples consistently demonstrate bulk superconductivity with a transition temperature Tc similar to 6.0 K significantly higher than those of the constituent compound ThMo2Si2C and its related analogs. Under magnetic fields, the superconducting state exhibits a nearly isotropic behavior, which is attributed to strong covalent interlayer coupling. First-principles calculations reveal a substantial contribution from the Mo-d orbitals near the Fermi level, which exhibit several band-crossing points. The enhancement in Tc can be attributed to the synergistic combination of the valence electron concentration and the inter-sublattice self-doping effect between the [Ru2Si2] and [Mo2Si2C] layers.

Topological Kagome magnets, characterized by nontrivial electronic band structures featuring flat band, Dirac cone and van Hove singularities, provide a new avenue for the realization of thermoelectric devices. Unlike the conventional longitudinal Seebeck effect, transverse thermoelectric (TE) effects like the Nernst effect have attracted growing interest due to their unique transverse geometry and potential advantages. Here, we report the observation of a significant transverse thermoelectric conductivity alpha A_zx of 15 A K-1m-1 at low temperatures, together with a pronounced anomalous Nernst effect in the Kagome antiferromagnet FeGe, which exhibits a charge density wave inside the antiferromagnetic (AFM) state. This value is the highest record among known AFM materials. Furthermore, the thermopower at 14 T increases by 102-104

The formamidinium copper formate [(NH2)2CH]Cu(HCOO)3 (FMD-Cu) with a perovskite-like structure based on a nonporous metal-organic framework (MOF), is presented for its synthesis and magnetic properties. The magnetic properties and their couplings to the structure are derived from detailed magnetic susceptibility and heat capacity measurements. We also discuss the spin exchange couplings based on density functional theory (DFT) calculations. As a result, FMD-Cu exhibits the unusual quasi-one-dimensional antiferromagnetic (AFM) characteristics with the N & eacute;el temperature TN = 12.0 K and an intrachain coupling constant J/kB approximate to 76.3 K. We also estimate the effective interchain coupling J*/kB approximate to 4.24 K, suggesting that FMD-Cu is close to an ideal candidate for one-dimensional magnet. Furthermore, the heat capacity shows a transition to an antiferromagnetic ordering state appears around TN. Besides, the nonzero parameter gamma = 0.089 J mol-1 K-1 obtained from the linear relationship, gamma T, to the low temperature-dependent zero-field heat capacity data, can be associated with the magnetic excitations in insulating quasi-one-dimensional AFM Heisenberg spin-1/2 chains. The experimental estimate and DFT calculations are entirely consistent with a model of FMD-Cu in which AFM exchange interactions originating from Jahn-Teller distortion of the Cu2+ (3d9) ions, leaving a sublattice of coupled ferromagnetic (FM) chains. Hence, FMD-Cu is proposed as a canonical model of a quasi-one-dimensional Heisenberg spin-1/2 antiferromagnetic material.

Locally noncentrosymmetric (LNC) superconductors with broken local inversion symmetry can exhibit exotic properties due to antisymmetric spin-orbit coupling (SOC). A promising strategy to construct LNC superconductors is to incorporate LNC blocks into superconducting lattices. Herein, a complex LNC superconductor, Th2Mo2Rh2Si4C, was designed and successfully synthesized. This compound adopts a unique 22241* structure, in which the superconducting [Mo2Si2C] block loses its out-of-plane mirror symmetry due to being sandwiched between antifluorite-type [Rh2Si2] and fluorite-type [Si2Rh2] layers. Physical property measurements indicate the title compound exhibits bulk superconductivity with a remarkably enhanced upper critical field μ0Hc2(0) of 1.39 T, five times higher than that of the constituent ThMo2Si2C, albeit with a similar transition temperature Tc = 2.1 K. First-principles calculations further reveal a Rashba-type SOC due to the lack of local inversion symmetry, which results in multiple gapped band crossings and significant band splitting near the Fermi level. This work provides a new material platform to study the interplay between superconductivity and Rashba-type SOC and lays a rational path for the exploration of LNC superconductors.

It is generally believed that electronic correlation, geometric frustration, and topology, individually, can facilitate the emergence of various intriguing properties that have attracted a broad audience for both fundamental research and potential applications. Here, we report a series of unconventional Hall effects observed in a single compound—quasi-kagome Kondo Weyl semimetal candidate Ce3TiSb5. In the paramagnetic phase, signature of dynamic c-f hybridization is revealed by a reduction of anomalous Hall effect and is connected to frustration-promoted incoherent Kondo scattering. A large topological Hall effect exceeding 0.2 μΩ ⋅ cm is found at low temperatures, which should be ascribed to the non-collinear magnetic texture. In addition, a peculiar loop-shaped Hall effect with switching chirality is also seen, which is inferred to be associated with magnetic domain walls that pin history-dependent spin chirality and/or Fermi-arc surface states projected from the in-gap Weyl nodes. These exotic results place Ce3TiSb5 in a regime of highly-frustrated antiferromagnetic dense Kondo lattice with a nontrivial topology on an “extended” global phase diagram, and highlight the interplay among electronic correlation, geometric frustration and topology. Electronic correlation, geometric frustration, and topology are known to individually drive intriguing properties in materials. Here, the authors explore these interactions in the quasi-kagome Kondo Weyl semimetal Ce3TiSb5, revealing unconventional Hall effects that underscore the complex interplay of these factors, with implications for understanding topological and magnetic phenomena

Two-dimensional (2D) magnetic materials are attracting significant interest due to their potential for exotic spin-dependent transport phenomena and spintronic applications. FePd2Te2 is a layered ferromagnet with quasi-1D zigzag Fe chains and features intrinsic crystal twinning. Combining angle-dependent magnetotransport, magneto-optical Kerr effect imaging, and theoretical calculations, we establish a twin-domain-induced linkage between microstructure and transport. This intrinsic twinning generates a pseudo-fourfold in-plane magnetic anisotropy. Angle-dependent magnetoresistance (AMR) measurements confirm the presence of fourfold-symmetry components in the ferromagnetic state, while magneto-optical Kerr microscopy directly visualizes orthogonal in-plane magnetic domains that correspond to the twin structure. First-principles calculations suggest the anomalous Hall effect originates from an intrinsic Berry curvature mechanism, driven by strong spin-orbit coupling. The twinning strongly suppresses the measured in-plane anomalous Hall conductivity relative to single-domain expectations, indicating structural twinning as an effective microstructural knob for tuning Berry-phase responses. These results reveal a clear structure-property relationship in a low-symmetry layered magnet and position FePd2Te2 as a platform for domain-engineered control of anisotropic magnetotransport in layered and low-dimensional ferromagnets.

The emergence of extremely large magnetoresistance in kagome compounds is rare yet highly intriguing, despite its presence in various other material systems. In this study, we report a comprehensive investigation of the specific heat, magnetotransport properties, electronic structure, and de Haas-van Alphen effect in the kagome compound Ni3In2Se2. This compound exhibits an impressive magnetoresistance of 8600% at 2 K and 9 T, along with a high carrier mobility of approximately 9000 cm2/V s. Hall measurements reveal an anomalous behavior at low temperatures, which is likely attributed to the multi-carrier effect. Density functional theory calculations suggest that the large anisotropic magnetoresistance in Ni3In2Se2 is primarily due to the geometry of its Fermi surfaces, which is further characterized by de Haas-van Alphen effect measurements. These results highlight Ni3In2Se2 as a promising platform for electronics and spintronics applications in kagome compounds.

As a prototypical altermagnet, RuO2 has been subject to many controversial reports regarding its magnetic ground state and the existence of the crystal Hall effect. We obtained a high-quality RuO2 single crystal with a residual resistivity ratio (RRR = 152), and carefully measured its magnetization, longitudinal resistivity (ρxx) and Hall resistivity (ρyx) in magnetic field up to 35 T. We also calculated its electronic bands and Fermi surface, and conducted numerical simulations for its transport properties. It was found that no magnetic transition occurs below 400 K, and that all the transport properties are consistent with the numerical simulation results, indicating that the magneto-transport properties originate from the intrinsic electronic structure and are dominated by the Lorentz force. Particularly, no crystal Hall effects were observed in our RuO2 samples and both magnetoresistance and Hall resistivity follow a scaling behavior. Additionally, by comparing theoretical calculations with experimental data, we found that the magneto-transport properties calculated using the altermagnetic structure are not consistent with the experimental observations, whereas those calculated based on the non-magnetic structure show excellent agreement. These results demonstrate that RuO2 is a typical semimetal, rather than an altermagnet. The altermagnet candidate RuO2 has sparked recent debate in the scientific community regarding its magnetic ground state and the existence of a crystal Hall effect. Here, the authors synthesize high-quality RuO2 crystals and provide comprehensive measurements to reveal that its magneto-transport properties obey scaling law and align with a non-magnetic semimetal model, challenging the notion of RuO2 as an altermagnet and refining our understanding of its electronic structure.

Kagome lattice can host abundant exotic quantum states such as superconductivity and charge density wave (CDW). Recently, successive orders of A-type antiferromagnetism (AFM), CDW and canted AFM have been manifested upon cooling in kagome FeGe. However, the mechanism of CDW and interaction with magnetism remains unclear. Here we investigate the evolution of CDW with temperature across the canted AFM by single-crystal x-ray diffraction, scanning tunneling microscope (STM) and resonant elastic x-ray scattering (REXS). For the samples with longer annealing periods, CDW-induced superlattice reflections become weak after the canted AFM transition, although long-range CDW order is still detectable by STM and REXS. We explore a long-range CDW order with suppressed structural modulation. Additionally, occupational modulations of Ge1 in the kagome plane and displacive modulations of all atoms were extracted. The results confirm Ge dimerization along the c axis and suggest a dynamic transformation between different CDW domains. Kagome materials have become a popular platform to investigate a range of competing quantum phases, such as the interplay between superconductivity and charge density waves (CDW). Here, the authors use x-ray diffraction, scanning tunneling microscopy and resonant elastic x-ray scattering to investigate the evolution of CDW ordering as a function of temperature in canted antiferromagnetic kagome FeGe. They find for post-annealed samples that the long-range CDW orders persist even as the structural modulations are suppressed although observations are highly dependent on the sample growth condition.

Anhydrous phosphate compounds based on 3d transition metal ions can exhibit rich physical behaviors in fundamental condensed matter physics. Herein, we report the structures and low-dimensional quantum magnetism in potassium-based phosphates, KMPO4 (M = Cu, Co), by cooperation of experimental investigations and first-principles density functional theory (DFT) calculations. Magnetic susceptibility measurement performed on KCuPO4 reveals the presence of strong quasi-one-dimensional antiferromagnetic (AFM) behavior with S=12 Cu2+ Heisenberg spin chains. The analysis of heat capacity data verifies the distinct AFM order occurs at TN = 14.1 K obtained from the -susceptibility, while cobalt phosphate KCoPO4 shows no magnetic ordering down to T = 1.9 K. Furthermore, the fairly small ratio of J*/|J| ≈ 3.85 × 10−2, where J/kB (=−141.86 K) is the nearest-neighbor spin-exchange coupling parameter estimated from susceptibility data and J*/kB (≈5.46 K) is the interchain coupling under the mean field approximation, respectively, providing additional evidence that KCuPO4 is almost an ideal one-dimensional AFM compound. Our DFT calculations confirmed that KCuPO4 has a magnetic sublattice in which one-dimensional AFM exchange interactions are weakly coupled ferromagnetic chains. In addition, significant magnetic frustrations are verified in both KCuPO4 and KCoPO4, implying the possibility of a quantum magnetic phase in this phosphate family.

The nonmagnetic kagome metal ScV6Sn6 displays an unconventional charge order (CO) accompanied by signatures of an anomalous Hall effect, hidden magnetism, and multiple lattice instabilities. In this study, we report the observation of unconventional anomalous thermoelectric properties. Notably, unexpected anomalous transverse Nernst signals reach a peak value of ∼4 µV/K near the TCDW ∼92 K in ScV6Sn6, and these signals persist in the charge-ordered state as the temperature decreases to 10 K. Furthermore, both thermopower and thermal conductivity exhibit significant changes under magnetic fields, even in the nonmagnetic ground state. These observations strongly suggest the emergence of time-reversal symmetry breaking in ScV6Sn6, as supported by muon spin relaxation (µSR) measurements. While hidden magnetism represents the most plausible origin, alternative mechanisms involving orbital currents and chiral charge order remain possible.

Materials with a kagome lattice naturally host topological electronic structures, giving rise to many intriguing quantum states within this family. In this study, we performed calculations of the electronic structure and Fermi surface, and measured the longitudinal resistivity ρ_{xx}(T,B), Hall resistivity ρ_{yx}(T,B), and quantum oscillations of the magnetization as a function of temperature and magnetic field for Pd_{3}Tl_{2}S_{2}, a kagome-lattice material. We observed an unsaturated extremely large magnetoresistance of 14 500% at 2 K and 9 T, the highest reported in kagome lattice materials, which was attributed to the carrier compensation supported by the Hall resistivity measurements. The band structure calculations, along with the observation of nontrivial Berry phases in the de Haas–van Alphen oscillations, demonstrate that Pd_{3}Tl_{2}S_{2} is a topological nodal-net (Hopf link) semimetal.

The transverse thermoelectric effect enables simpler, more flexible thermoelectric devices by generating electricity perpendicular to heat flow, offering promising solutions for waste heat recovery and solid-state cooling applications. Here, we report a striking observation of zero-field anomalous Hall effect (AHE) and anomalous Nernst effect (ANE) below TC in the two-dimensional metallic magnet FePd2Te2. The anomalous Nernst signal SAyxpeaks a maximum value of 0.15 mu V/ K at 100 K, much larger than that of conventional FM materials. Remarkably, the derived ratio aAij /sigma A in FePd2Te2 approaches the fundamental limit of kB/ e = 86 mu V/K. Our ij findings suggest a dominant Berry curvature contribution to the ANE. The observed giant zero-field anomalous Nernst response in 2D FePd2Te2 not only advances fundamental understanding of transverse thermoelectricity in layered magnets, but also provides this material as a promising candidate for practical thermoelectric spintronic applications.

Electron correlation often gives birth to various orders in quantum materials. Recently, a strongly correlated kagome antiferromagnet FeGe is discovered to undergo a charge density wave transition inside the A-type antiferromagnetic state, providing an opportunity to explore the interplay between charge order and magnetism. Here, we reported the observation of anisotropic resistivity and Hall effect, along with a topological Hall effect, in the annealed FeGe crystals. As the current flows along the ab-plane, the temperature dependence of ρab exhibits a distinct resistivity loop related to a first-order transition at Tcdw. The applied magnetic fields do not alter Tcdw but can induce a spin-flop transition at Hsf. Consequently, a field-induced large topological Hall effect is observed in the canting antiferromagnetic (CAFM) state below Tcant, which is possibly attributed to the non-trivial spin texture during the spin-flop process. Whereas, as current is parallel to c-axis, both the field-induced transitions in ρc and χc disappear. Instead, the Hall resistivity in the annealed FeGe significantly exhibits a deviation from the linear field-dependent. These findings provide valuable insight into revealing the interplay among magnetism, charge order and topology in the kagome magnets.

The square-net ferromagnet NdMn2Ge2 has attracted significant attention owing to its zero-field skyrmionic bubbles at room temperature and the associated intriguing topological transport phenomena. Compared with the other members of the RMn2Ge2 family (R = rare-earth elements), this compound exhibits a notably more complex and diverse magnetic structure. In this work, we present a systematic investigation of the magnetic properties of NdMn2Ge2. The magnetism predominantly arises from the Mn sublattice across a broad temperature range, with Nd moments becoming significant only at lower temperatures. With increasing external magnetic field applied along the c axis, the ferromagnetic transition temperature Tc shifts to higher temperatures, whereas the spin reorientation temperature TSR decreases. Based on these observations, we construct a detailed magnetic phase diagram and interpret the field-induced evolution of the topological magnetic states from an energetic standpoint. Critical exponents extracted from isothermal magnetization curves reveal that the magnetic exchange interaction decays as J(r) similar to r-4.59, placing it between short-range and long-range interaction regimes. This intermediate range suggests the coexistence of both interaction types, which may underpin the formation of skyrmionic bubbles in NdMn2Ge2. Furthermore, NdMn2Ge2 exhibits a maximum magnetic entropy change of 4.16 J kg-1 K-1 and a relative cooling power of 218 J kg-1 at 70 kOe near room temperature. Our results provide a deeper understanding of the magnetic interactions in NdMn2Ge2 and shed light on the relationship between its complex magnetic behavior and emergent topological spin textures.

In magnetic topological materials, the interplay between magnetism and nontrivial topology gives rise to exotic quantum transport phenomena, including the anomalous Hall effect and anomalous Nernst effect. Here,we report the observation of intrinsic topological Hall and topological Nernst effects below the Néel temperature（T N = 25 K） in the antiferromagnetic（AFM） topological insulator Mn Bi 2 Te 4 . The maximum of topological Hall resistivity reaches approximately 9 μΩ·cm at 2 K, while the topological Nernst signal attains a peak value of0.1 μV/K near 10 K. These anomalous transport behaviors originate from the net Berry curvature induced by the non-collinear spin structure in the canted AFM state. Our results suggest a close connection between the topological thermoelectric effect and non-collinear AFM order in AFM topological insulators.

It is generally believed that electronic correlation, geometric frustration, and topology, \textit{individually}, can facilitate the emergence of various intriguing properties that have attracted a broad audience for both fundamental research and potential applications. Here, we report a systematic investigation on a quasi-kagome Kondo Weyl semimetal candidate Ce$_3$TiSb$_5$. A series of unconventional Hall effects are observed. In the paramagnetic phase, signature of dynamic $c$-$f$ hybridization is revealed by a reduction of anomalous Hall effect and is connected to frustration-promoted incoherent Kondo scattering. A large topological Hall effect exceeding 0.2 $\mu\Omega$ cm is found at low temperatures, which should be ascribed to the noncolinear magnetic structures of the frustrated quasi-kagome lattice. In addition, a peculiar loop-shaped Hall effect with switching chirality is also seen, which is inferred to be associated with magnetic domain walls that pin history-dependent spin chirality and / or Fermi-arc surface states projected from the in-gap Weyl nodes. These exotic results place Ce$_3$TiSb$_5$ in a regime of highly-frustrated antiferromagnetic dense Kondo lattice with a nontrivial topology on an ``extended" global phase diagram, and highlight the interplay among electronic correlation, geometric frustration and topology.