Abstract The fractional quantum Hall effect at half-filled Landau levels provides a promising route to unusual topological phases that may host non-Abelian excitations, but these states are often fragile and difficult to control experimentally. Here, we report the observation of a cascade of even-denominator fractional quantum Hall states at fillings ν = −5/2, −7/2, −9/2, −11/2 and −13/2, alongside numerous odd-denominator states in mixed-stacked pentalayer graphene—a system characterized by intertwined quadratic and cubic band dispersions. These even-denominator states emerge from two distinct intra-zeroth Landau levels and exhibit displacement-field tunability. At half fillings, continuous quantum phase transitions between even-denominator states, magnetic Bloch states, and composite Fermi liquids are clearly identified upon tuning external fields. Numerical calculations support possible Moore–Read type pairing for even-denominator states, although direct probes of their exchange statistics remain important for future experiments. These results establish mixed-stacked graphene as a versatile platform for tunable correlated topological phases.

The ability to manipulate and detect the parity of quantum states in superconductor-semiconductor hybrid systems is pivotal to realizing the promise of topological quantum computation. However, as these architectures scale toward artificial Kitaev chains with phase-control loops, local accessibility becomes restricted, constraining conventional local parity control and detection. While Andreev molecules offer a platform for non-local intervention, deterministic protocols for parity manipulation have yet to be experimentally established. Here, we demonstrate deterministic non-local control over the parity configuration of a quantum dot (QD) by electrically modulating the coherent hybridization with a spatially adjacent QD within an Andreev molecule. By systematically investigating three distinct joint parity configuration regimes in the elastic co-tunneling limit, we experimentally uncover the operational conditions for this non-local control. In conjunction with theoretical simulations establishing a global phase diagram, we identify a set of universal selection rules governing parity transitions, dictated by the symmetry-imposed interplay between the joint parity configuration and the dominant inter-dot coupling mechanism (elastic co-tunneling vs. crossed Andreev reflection). Furthermore, we establish the supercurrent, directly signaled by zero-bias conductance peaks, as an intrinsic, sensor-free probe of the parity configuration, obviating the need for auxiliary charge sensors. Our results provide a validated physical framework for parity engineering, offering a key building block for scalable, multi-QD superconducting architectures.

Abstract Hall effect is an important phenomenon when a magnetic field is applied to materials. From the curve depicting the Hall resistance versus the magnetic field, crucial information such as carrier concentration can be extracted. If the curve exhibits a linear dependence up to rather high magnetic fields, it indicates that charge transport involves only a single type of carrier, and if a non-linear curve is measured, then the double-carrier model should be considered for fitting. However, this model involves four unknown parameters, including the concentration and mobility of the two carriers, resulting in that such fitting is usually non-unique, which significantly reduces the reliability and accuracy. In this work, a double-carrier platform was constructed on a probable excitonic insulator Ta 2 Pd 3 Te 5 and the four-parameter fitting based on the double-carrier model was simplified to a single-parameter fitting by employing methods such as analyzing the shape of the Hall resistance curve and generating gate-induced Shubnikov-de Haas oscillations. Thus, we provide a reliable method for double-carrier fitting of Hall resistance and a new evidence for the existence of excitonic-insulator state in Ta 2 Pd 3 Te 5 .

In recent decades, there has been a persistent pursuit of applications for surface/edge states in topological systems, driven by their dissipationless transport effects. This work demonstrates the remarkable properties of the topological material Ta2Pd3Te5, as a thermometer. At low temperatures, it shows a power-law correlation in temperature-dependent resistance, while behaving like a semiconductor at high temperatures. This dual behavior effectively mitigates the issue of infinite resistance in semiconductor thermometers at ultra-low temperatures, making it ideal for millikelvin-range refrigerators. Through chemical doping, thickness adjustment, and gate voltage control, its performance can be finely tuned, and can also enable micron-scale local temperature measurement from millikelvin to room temperature. Furthermore, this thermometer exhibits excellent temperature sensitivity and resolution, and can be fine-tuned to show small magnetoresistance. In summary, the Ta2Pd3Te5-based thermometer, also referred to as a topological thermometer, demonstrates considerable potential for broad-temperature-range detection and merits further investigation and optimization.

Helically twisted multilayers offer access to moiré physics beyond the single-superlattice paradigm, yet their correlated and topological transport properties remain largely unexplored in semiconductor moiré materials. Here we report magnetotransport measurements of helical trilayer WSe2, in which two coupled moiré patterns relax into a supermoiré landscape composed of inequivalent local topological domains with distinct electronic structures and unequal spatial areas. By electrostatic tuning, we identify a trilayer-hybridized regime where interactions and real-space reconstruction combine to generate a plethora of magnetic and topological states absent in the twisted bilayers. At moiré filling factor ν = -1, we observe a ferromagnetic insulating state that is robust against magnetic field and accompanied by a non-quantized anomalous Hall response -4 kOhms. This behaviour is consistent with a time-reversal-symmetry-breaking supermoiré Chern mosaic, in which the Hall response arises from the non-cancelling contributions of local domains with opposite Chern character arranged by the relaxed structure. Under strong magnetic fields, a symmetry-broken Chern insulating state (C = 1) emerges near ν = -2/3, displaying a much larger positive Hall response together with strongly enhanced longitudinal resistance, suggestive of field-reconstructed topological minibands and domain-boundary scattering. These results establish relaxed supermoiré semiconductor trilayers as a platform for spatially organized magnetism and topology beyond the bilayer limit.

We systematically investigate the transport and photoluminescence measurements of a high-mobility twodimensional electron gas in a GaAs/AlGaAs quantum well under magnetic fields B. By tuning the laser excitation power P-ex, transitional patterns of the singlet and triplet (negative charged) trions occur in the high-B regime: The two branches of singlet trions X-s(-) dominate at low P-ex (<1 W/mm(2)), and six more triplet X(t)(- )branches emerge at high P-ex (similar to 1 - 10 W/mm(2)). At extremely high laser P-ex (>100 W/mm(2)) and at fixed B fields, robust Fano resonance features are accompanied by the Gaussian resonance centered at X-s(-), which illustrates dark and bright trions. Therefore, a very high laser excitation (or electromagnetic field) becomes an efficient tool to probe dark trions. In addition, discontinuity and splitting features occur at fillings v = 2, 4, 6, and the abrupt drops at high odd fillings factors (v similar to 5, 7, 9, etc.) originate from spin-resolved many-body interactions.

The combination of ferromagnetism, superconductivity, and spin-orbit coupling in interfacial two-dimensional electron liquids (2DELs) assembles the essential ingredients for realizing tantalized topological or spin polarized superconductivity for interfacial oxitronics. Unfortunately, these ingredients usually compete and are sometimes mutually exclusive. Here, by optimally designing a ferromagnet/superconductor heterostructure (LaAl0.7Mn0.3O3/SrTiO3), we demonstrate a ferromagnetic 2DEL with strong Rashba spin-orbit coupling and typical superconducting behavior. More excitingly, Rashba spin-orbit coupling and ferromagnetic order were found to coexist according to the observation of weak antilocalization and butterfly shaped magnetoresistance with clear hysteresis during the superconducting transition. Our revealed coexistence of ferromagnetism, superconductivity, and spin-orbit coupling at the oxide interface provides a fruitful platform to investigate nontrivial properties of spin-polarized supercurrent/topological superconductors and to cultivate applications for superconducting spintronics/quantum computation.

Superconducting diodes, characterized by unidirectional flow of supercurrents, are promising components for low-power quantum circuits. In this work, we demonstrate a field-controlled superconducting rectifier in a van der Waals heterostructure comprising an Ising superconductor NbSe2 and an antiferromagnetic insulator MnPS3. Our devices display key features of a superconducting-vortex-diode effect, including a characteristic M-shaped dependence of the critical current Ic on out-of-plane magnetic fields Bz, and an antisymmetric diode efficiency 0 with respect to Bz. The second-harmonic magnetotransport measurements confirm that the observed nonreciprocity originates from the strongly asymmetric vortex dynamics, which are significantly enhanced compared to pristine few-layer NbSe2. We attribute the enhancement to an inversion symmetry breaking induced by the spatially distributed superconducting domains due to the inhomogeneous magnetic proximity effect. Our findings bring insights for developing superconducting-vortex diodes that do not rely on artificial edge or surface disorder to achieve asymmetric barriers for vortex motion.

Spin-orbit torque (SOT) driven magnetization switching in all-van der Waals (vdW) heterostructures is a promising route toward next-generation, high-density spintronic memories. Improving switching efficiency and achieving nanosecond-scale operation are essential for practical applications. Here, we demonstrate room-temperature, field-free SOT magnetization switching in WTe2/Fe3GaTe2 heterostructures, achieved through an optimized fabrication process. The device achieves a high switching ratio of 90% at a low current density on the order of 10(5) A/cm(2). Moreover, we demonstrate nanosecond-timescale magnetization switching while maintaining high switching ratio and energy efficiency. These results advance the viability of all-vdW heterostructures for energy-efficient, high-speed memory applications.

Abstract The ground-state parity in superconductor-semiconductor hybrid systems indeed plays a pivotal role in both the pursuit of Majorana zero modes (MZMs) and the development of topological qubits. Here, we report the gate control of a ground-state parity switch in an InAs-Al hybrid nanowire Coulomb island without the Zeeman effect. The evolution in Coulomb-blockaded spectroscopy reveals a gate-driven crossing of a subgap state through zero energy, revealing characteristics of a spin-polarized Andreev bound state (ABS). Our findings indicate the presence of spin splitting without a Zeeman field and demonstrate the potential for parity manipulation via purely electrostatic control and modulation.

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.

Fe3Sn2, a ferromagnetic metal with a kagome lattice, serves as an ideal platform for exploring topological electronic states and Berry curvature due to its unique band structure. However, systematic reports on the transport properties of Fe3Sn2 nanosheets remain scarce. We present temperature-dependent transport property measurements of Fe3Sn2 nanosheets synthesized via chemical vapor deposition on Si/SiO2 substrates. The samples exhibit a robust anomalous Hall effect from 40 K to 300 K, along with a magnetoresistance sign reversal at 40 K at high magnetic fields, indicating a spin reorientation from in-plane to out-of-plane. Notably, a sharp crossover in the dominant transport contribution from electrons to holes near 200 K is observed, accompanied by distinct anomalous Hall behaviors in the two regimes, indicating a temperature-induced Lifshitz transition within the multi-band system. This divergence is potentially linked to a topological reconstruction of the Fermi surface across the transition. Our findings highlight the tunability of topological transport in two-dimensional kagome magnets and provide new insights into the interplay between band topology, dimensionality and magnetic order.

Hall effect is an important phenomenon when a magnetic field is applied to materials. From the curve depicting the Hall resistance versus the magnetic field, crucial information such as carrier concentration can be extracted. If the curve exhibits a linear dependence up to rather high magnetic fields, it indicates that charge transport involves only a single type of carrier, and if a non-linear curve is measured, then the double-carrier model should be considered for fitting. However, this model involves four unknown parameters, including the concentration and mobility of the two carriers, resulting in that such fitting is usually non-unique, which significantly reduces the reliability and accuracy. In this work, a double-carrier platform was constructed on a probable excitonic insulator Ta2Pd3Te5, and the four-parameter fitting based on the double-carrier model was simplified to a single-parameter fitting by employing methods such as analyzing the shape of the Hall resistance curve and generating gate-induced Shubnikov-de Haas oscillations. Thus, we provide a reliable method for double-carrier fitting of Hall resistance and a new evidence for the existence of excitonic-insulator state in Ta2Pd3Te5.

The missing first Shapiro step in microwave-irradiated Josephson junctions has been widely interpreted as a hallmark of Majorana bound states. However, conventional mechanisms like junction underdamping or Joule heating can produce similar signatures. Here, we demonstrate that the intrinsic non-linear current-voltage characteristic of low-to-moderate transparency junctions can also suppress the first step, accompanied by distinctive zigzag boundaries between the zeroth and first step at intermediate driving frequencies. Microwave measurements on Al/WTe2 junctions and numerical simulations of a non-linear resistively and capacitively shunted junction model reveal the first-step collapse induced by switching jumps of current, together with zigzag features absent in scenarios solely driven by finite beta\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\beta$$\end{document} or Joule heating. This zigzag signature, therefore, provides a crucial diagnostic tool, emphasizing the necessity of comprehensive analysis of microwave spectra before attributing the absence of the first Shapiro step to Majorana physics.

In the past two decades, enormous efforts have been made to search for possible platforms and schemes to implement topological quantum computation (TQC). In exploring the Fu-Kane scheme of TQC based on Josephson trijunctions constructed on topological insulators, the predicted Majorana phase diagram of an individual trijunction has already been verified experimentally. If Majorana zero modes indeed exist in this kind of trijunction, coupling between them in multiple trijunction devices should be further expected. In this study, we fabricated Josephson devices containing two adjacent Josephson trijunctions on the surface of Sn-(Bi, Sb)2(Te, S)3 and observed a possible signature of the coupling effect manifesting as the reopening of a minigap in both trijunctions where a closure would otherwise be expected if the trijunctions existed individually. While alternative interpretations cannot be fully ruled out, our findings provide experimental support for the validity of the Fu-Kane theory and provide further motivation for advancing the TQC scheme proposed by Fu and Kane.

Quantum oscillations, the oscillatory behavior of electrical and thermodynamic properties, are typically observed in metals and vanish in the quantum limit under strong magnetic fields1. Phenomena such as the fractional quantum Hall effect2, the Hofstadter butterfly3,4, and recent observations of quantum oscillations in exotic insulators are notable exceptions5-12. The narrow-gap Dirac semiconductor ZrTe5, a less exotic material without strong correlations or artificially engineered superlattices, nevertheless exhibits resistance oscillations in the quantum limit13 but can be interpreted within a simple Zeeman-effect-based picture14,15, which remains conventional quantum oscillations without exotic properties. Here, we report the observation of unexpected mini-oscillations superimposed on Zeeman-effect-induced main oscillations in the quantum limit. The subtracted mini-oscillations are periodic in 1/B with the highest frequency equal to 2.1

Quantized conductance in quasi-one-dimensional systems not only provides a hallmark of ballistic transport, but also serves as a gateway for exploring quantum phenomena. Recently, a unique hidden Rashba effect, which arises from the compensation of opposite spin polarizations of a Rashba bilayer in inversion symmetric crystals with dipole fields, such as bismuth oxyselenide (Bi_{2}O_{2}Se), has attracted tremendous attention. However, investigating this effect utilizing conductance quantization remains challenging. Here we report the conductance quantization observed in a chemical vapor deposition (CVD)-grown high-mobility Bi_{2}O_{2}Se nanoribbon, where quantized conductance plateaus up to 44×2e^{2}/h (e is the elementary charge, h is the Planck's constant, and the factor 2 results from spin degeneracy) are achieved at zero magnetic field. Because of the hidden Rashba effect, the quantized conductance remains in multiples of 2e^{2}/h without Zeeman splitting even under magnetic field up to 12 T. Moreover, within a specific range of magnetic field, the plateau sequence follows the Pascal triangle series, namely, (1,3,6,10,15…)×2e^{2}/h, reflecting the interplay of size quantization in the two transverse directions. These observations are well captured by an effective hidden Rashba bilayer model. Our results demonstrate Bi_{2}O_{2}Se as a compelling platform for spintronics and the investigation of emergent phenomena.

Quantum anomalous Hall effect (QAHE) in graphene moiré superlattices has drawn considerable and sustained attention, owing to both fundamental interests of Chern insulators and promising applications in topological electronics. An empirical regularity suggests that QAHE manifests exclusively at odd-electron filling per moiré unit cell, whereas even-filling configurations-particularly at half-filled bands-invariably yield topologically trivial insulators. This dichotomy, originating from quantum states competition, has been the key issue in theoretical investigations of topology and correlation, but its universality remains an open question. Here we demonstrate a violation of this paradigm in rhombohedral heptalayer graphene/hexagonal boron nitride moiré superlattices, where a robust Chern insulator emerges at two-electron filling per moiré unit cell. It wins the competition with a trivial correlated insulator only above a critical displacement field as large as ∼1  V/nm. The odd Chern number C=1 for the filling of 2 is intriguing: theoretical calculation shows that electrons occupy two interaction-renormalized bands with distinct spin-valley flavors, whose charge densities arrange into dual honeycomb and triangular lattices, leading to a total Chern number of 1 and minimized Coulomb repulsion. Our findings broaden the landscape for engineering nontrivial topological states, while providing critical insights into the delicate competition between emergent quantum phases in strongly correlated moiré systems.

Graphene multilayers exhibit electronic spectra that depend sensitively on the layer number and stacking order. Here, we investigate ABCBC-stacked pentalayer graphene, a non-centrosymmetric mixed stacking that combines a rhombohedral trilayer-like cubic band and a Bernal bilayer-like parabolic band. Transport measurements reveal an intrinsic gap at charge neutrality that evolves strongly asymmetrically under a perpendicular displacement field, evidencing built-in layer polarization from broken inversion and mirror symmetry. By tuning the displacement field and carrier density, we drive multiple Lifshitz transitions and observe Landau levels with distinct degeneracies arising from the multi-flatband structure. Remarkably, a ν = -6 quantum Hall state emerges at an exceptionally low magnetic field of ∼20 mT. These results demonstrate that mixed-stacked multilayer graphene provides a tunable platform in which non-centrosymmetric symmetry breaking, multiple flatbands, and unusual quantum Hall physics coexist, opening opportunities to explore emergent correlated and topological electronic states.