Fang Yuqiang

• Doctor of Engineering
• Chinese Academy of Sciences

Magnetic transition metal dichalcogenides exhibit unique spintronic properties, making them highly promising for advanced spintronic devices. It is unpreparable 1T NbTe2, rather than the stable 1T’ phase, that has been theoretically predicted to host nontrivial topology, but its thermodynamic structural instability hinders its development in spintr...

The design and fabrication of ultrafine nanostructures in two-dimensional (2D) van der Waals materials are crucial for the functionalization of electronic devices. Here, we report the utilization of far-field femtosecond laser patterning to fabricate super-resolution nano-groove array (NGA) structures in 2D multilayer NbOI2 in ambient air, achievin...

The electrocatalytic conversion of NO3⁻ and CO2 into urea features a potential means of reducing carbon footprint and generating value‐added chemicals. Nonetheless, due to the limited efficiency of carbon−nitrogen (C─N) coupling and the competing side reaction that forms ammonia, the urea selectivity and production yield have remained low. In this...

1D transition metal dichalcogenide (TMD) nanowires (NWs) have attracted attention to act as energy storage and information technology materials, but the TMD NWs are unable to directly synthesized rather than hexagonal flakes due to the habit of in‐planar isotropic crystal growth. Herein, the topological phase transformation is proposed to synthesiz...

Transition metal carbo‐chalcogenides (TMCCs), a novel class of 2D materials, combining the distinctive properties of transition metal dichalcogenides (TMDs) and MXenes, eliciting considerable interest for their excellent properties across various fields. However, TMCCs' optical properties and potential in ultrafast photonics remain unexplored. This...

Layered transition metal trithiophosphates (TMPS3, TM = Mn, Fe, Co, etc.) with high theoretical capacity (>1 300 mAh g⁻¹) are potential anode materials for sodium‐ion batteries (SIBs). However, the strong bonding between P2 dimers and S atoms in TMPS3 hinders the efficient alloying reaction between P2 dimers and Na⁺, resulting in practical capaciti...

As a newly discovered Janus van der Waals (vdW) material, semiconducting Nb3SeI7 offers several notable advantages, including spontaneous out‐of‐plane polarization, facile exfoliation to the monolayer limit, and significant out‐of‐plane emission dipole in second harmonic generation. These properties make it a promising candidate for piezoelectric a...

2D transition metal halide oxides (TMHOs) have attracted much interest due to their intriguing ferroelectrics and excellent nonlinear optics, however, their susceptibility to oxidation makes their basic research and practical application a challenge. Therefore, it is crucial to understand the oxidation mechanism and explore effective strategies for...

Two-dimensional transition metal trithiophosphates (TMPS3, TM = Mn, Fe, Co, etc.) are competitive anode materials for sodium-ion batteries (SIBs) due to their high theoretical capacity (>1,300 mAh g−1) but suffer from limited practical capacity (∼300 mAh g−1) and inferior rate capability caused by sluggish Na+ intercalation/deintercalation kinetics...

To achieve logic operations via Majorana braiding, positional control of the Majorana bound states (MBSs) must be established. Here we report the observation of a striped surface charge order coexisting with superconductivity and its interaction with the MBS in the topological superconductor 2M-WS2, using low-temperature scanning tunneling microsco...

In van der Waals heterostructures (vdWHs), the manipulation of interlayer stacking/coupling allows for the construction of customizable quantum systems exhibiting exotic physics. An illustrative example is the diverse range of states of matter achieved through varying the proximity coupling between two-dimensional (2D) quantum spin liquid (QSL) and...

The realization of spontaneous ferroelectricity down to the one‐dimensional (1D) limit is both fundamentally intriguing and practically appealing for high‐density ferroelectric and nonlinear photonics. However, the 1D vdW ferroelectric materials are not discovered experimentally yet. Here, the first 1D vdW ferroelectric compound NbOI3 with a high C...

1D layered nanowires (NWs) are expected to be excellent electrode materials due to their efficient electron/ion transport and strain/stress relaxation. However, it is a great challenge to synthesize layered NWs by a top‐down synthetic route. Herein, ultralong 1D layered K0.5Mn0.75PS3 NWs (length: >100 µm; diameter: ≈300 nm) are synthesized for the...

Diode effects are of great interest for both fundamental physics and modern technologies. Electrical diode effects (nonreciprocal transport) have been observed in Weyl systems. Optical diode effects arising from the Weyl fermions have been theoretically considered but not probed experimentally. Here, we report the observation of a nonlinear optical...

van der Waals (vdWs) interchain coupling is a unique feature of 1D vdWs materials, where strong vdWs coupling in 1D vdWs materials leads to the thickness‐dependent physical properties, while weak vdWs coupling can preserve the single‐chain property even in their thick counterparts. Different from 2D vdWs materials, due to their nanoscale widths, id...

As a new group of van der Waals (vdWs) ferroic materials, transition metal dioxydihalides MO2X2 (M: Mo, W; X: halogen) with a perovskite‐like structure are theoretically predicted to exhibit intriguing physics and versatile ferroic characteristics, which is not achieved experimentally as far as it is known. In this work, the robust ferroelasticity...

Metallic 2M or 1T′-phase transition metal dichalcogenides (TMDs) attract increasing interests owing to their fascinating physicochemical properties, such as superconductivity, optical nonlinearity, and enhanced electrochemical activity. However, these TMDs are metastable and tend to transform to the thermodynamically stable 2H phase. In this study,...

The intrinsically superconducting Dirac semimetal 2 M − WS 2 is a promising candidate for realizing proximity-induced topological superconductivity in its protected surface states. A precise characterization of the bulk superconducting state is essential to understand the nature of surface superconductivity in the system. Here, we report a detailed...

A quasi-zero strain mechanism for high-capacity sodium storage of Nb 4 P 2 S 21 revealed by in situ XRD and density functional theory (DFT) calculations.

Molybdenum disulfide (MoS 2 ) with high theoretical capacity has been viewed as a promising anode for sodium‐ion batteries, but suffers from inferior rate capability owing to the polaron‐induced slow charge transfer. Herein, we proposed a polaron collapse strategy induced by electron‐rich insertions to effectively solve the above issue. Specificall...

2D ferroelectric materials have attracted much interest due to their potential for developing flexible self‐powered nanogenerators. Niobium oxide diiodide (NbOI 2 ) has in‐plane anisotropy of electrical properties and large lateral piezoelectric coefficient, which makes it possess high‐performance and unique behavior in flexible sensing. In this wo...

Tracking the mechanism behind the unconventional superconductors has been recognized as a great challenge and remains one of the major problems in multifields. Layered transition metal dichalcogenides (TMDs) offer an important platform for exploring novel physics. Here, we have discovered that the synergetic Re doping and pressure effect on VSe2 pr...

Recently, V-based Kagome metals have attracted intense attention due to the coexistence of their topological nontrivial electronic structure, charge density wave, and superconductivity. Here, we report the fabrication and physical investigations of single-crystalline thin flakes of the Kagome metal KV3Sb5. For samples with a thickness of 22±2 nm ,...

2D in‐plane ferroelectric NbOI2 exhibits strong second harmonic generation (SHG) and ultrahigh effective susceptibility. To push forward their applications in nonlinear photonics and optoelectronics, it is highly desirable to understand the emission dipole orientation and tunability of SHG, which is not achieved. Here, by integrating tight focusing...

Majorana bound states (MBSs) are building blocks for topological quantum computing. They can be generated via the combination of electronic topology and superconductivity. To achieve logic operations via Majorana braiding, positional control of the MBS must be established. To this end, exotic co-existing phases or collective modes in an intrinsic t...

Alloying-type metal sulfides with high sodiation activity and theoretical capacity are promising anode materials for high energy density sodium ion batteries. However, the large volume change and the migratory and aggregation behavior of metal atoms will cause severe capacity decay during the charge/discharge process. Herein, a robust and conductiv...

Weyl semimetals have emerged as a promising quantum material system to discover novel electrical and optical phenomena, due to their combination of nontrivial quantum geometry and strong symmetry breaking. One crucial class of such novel transport phenomena is the diode effect, which is of great interest for both fundamental physics and modern tech...

As a member of the emerging MXenes family, Nb2CS2 offers distinctive superconductivity, excellent electrical properties, and outstanding chemical stability, making it potentially useful for energy storage, medical imaging, and quantum computing. Herein, we systematically investigate how ultrahigh pressure affects the electrical properties of Nb2CS2...

Intercalation anodes usually exhibit better cyclability than conversion and alloying anodes for lithium or sodium storage due to the robust layered structure. However, for larger‐sized potassium accommodation, these intercalation anodes usually undergo huge layer expansion and structural distortion, triggering severe capacity fading. Herein, the no...

Two-dimensional (2D) van der Waals (vdW) materials, featuring relaxed phase-matching conditions and highly tunable optical nonlinearity, endow them with potential applications in nanoscale nonlinear optical (NLO) devices. Despite significant progress, fundamental questions in 2D NLO materials remain, such as how structural distortion affects second...

Access to new superconducting phases in transition-metal dichalcogenides (TMDs) via pressure treatment has been the primary target in this field. As equally essential as the fabrication of new superconducting materials at high pressure, maneuvering new superconducting phases at moderate pressures is also one of the core goals in the synthesis commu...

Alloying‐type bismuth with high volumetric capacity has emerged as a promising anode for sodium‐ion batteries but suffers from large volume expansion and continuous pulverization. Herein, a coordination constraint strategy is proposed, that is, chemically confining atomic Bi in an intercalation host framework via reconstruction‐favorable linear coo...

Metastable 1T′-phase transition metal dichalcogenides (TMDs) attract increasing interests owing to their fascinating physicochemical properties in superconductors, optical materials, and energy storage. However, spontaneous 1T′ to 2H phase transition severely hinders practical application of 1T′ TMD. In this study, through systematic investigation...

Second harmonic generation (SHG) of 2D crystals has been of great interest due to its advantages of phase‐matching and easy integration into nanophotonic devices. However, the polarization‐dependence character of the SHG signal makes it highly troublesome but necessary to match the laser polarization orientation relative to the crystal, thus achiev...

Recently V-based Kagome metal attracted intense attention due to the coexistence of topological nontrivial electronic structure, charge density wave, and superconductivity. Here we report the fabrication and physical investigations of the single-crystalline thin flakes of the Kagome metal KV 3 Sb 5 . For the samples with the effective superconducti...

Molybdenum disulfide (MoS 2 ) with high theoretical capacity has been viewed as a promising anode for sodium-ion batteries, but suffers from inferior rate capability owing to the polaron-induced slow charge transfer. Herein, we proposed a polaron collapse strategy induced by electron-rich insertions to effectively solve the above issue. Specificall...

Flexible piezosensing electronic skins (e-skins) have attracted considerable interest owing to their applications in real-time human-health monitoring, human-machine interactions, and soft bionic robot perception. However, the fabrication of piezosensing e-skins with high sensitivity, biological affinity, and good permeability at the same time is c...

The quantum spin Hall (QSH) effect has attracted extensive research interest because of the potential applications in spintronics and quantum computing, which is attributable to two conducting edge channels with opposite spin polarization and the quantized electronic conductance of 2e2/h. Recently, 2M-WS2, a new stable phase of transition metal dic...

Two‐dimensional (2D) ferroelectrics have attracted considerable attention due to their potential in the development of devices of miniaturization and multifunction. Although several van der Waals (vdW)‐layered materials show ferroelectricity, the experimental demonstrations of ferroelectric behavior in monolayers are very limited. Here we report th...

The investigation of two-dimensional atomically thin superconductors—especially those hosting topological states—attracts growing interest in condensed-matter physics. Here we report the observation of spin–orbit–parity coupled superconducting state in centrosymmetric atomically thin 2M-WS2, a material that has been predicted to exhibit topological...

Inducing new phases of transition metal dichalcogenides by controlling the d‐electron‐count has attracted much interest due to their novel structures and physicochemical properties. 1T’’ ReSe2 is a promising candidate for sodium storage, but the low electronic conductivity and limited active sites hinder its electrochemical capacity. Herein, new‐ph...

The quantum spin Hall (QSH) effect has attracted extensive research interest because of the potential applications in spintronics and quantum computing, which is attributable to two conducting edge channels with opposite spin polarization and the quantized electronic conductance of 2e2/h. Recently, 2M-WS2, a new stable phase of transition metal dic...

Active electronic states in transition metal dichalcogenides are able to prompt hydrogen evolution by improving hydrogen absorption. However, the development of thermodynamically stable hexagonal 2H-MoS2 as hydrogen evolution catalyst is likely to be shadowed by its limited active electronic state. Herein, the charge self-regulation effect mediated...

Metastable two-dimensional transition metal dichalcogenides (TMDs) are ideal electrocatalysts because of their excellent conductivities and high activities. However, metastable TMDs are generally unstable under electrochemical testing, especially after exfoliation with exposed abundant active sites. 2M-WS2, a typical TMD material with synergic meta...

GaFeO 3 -type oxides are promising multiferroic materials due to the coexistence of spontaneous magnetization and ferroelectric polarization properties at room temperature. As these ferroic properties feature a large anisotropy, single crystals are required. However, the magnetization of GaFeO 3 -type single crystals remains low at room temperature...

The discovery of two‐dimensional (2D) van der Waals (vdW) magnetic materials is of great significance to explore intriguing 2D magnetic physics and develop innovative spintronic devices. Herein, a new quasi‐one‐dimensional (1D) vdW layered compound CrZr4Te14 is successfully synthesized. Owing to the existence of 1D [CrTe2] and [ZrTe3] chains along...

Two-dimensional (2D) metal sulfides have been an emerging material group for high-performance and power-saving gas sensing. However, relatively little attention is paid to developing doping-driven approaches to improve their gas interaction properties, particularly at room temperature. In this work, we realize room-temperature reversible NO2 gas se...

Layered transition metal dichalcogenide rhenium selenide (ReSe2) has attracted great attention as an electrocatalyst for the hydrogen evolution reaction (HER) due to its excellent stability and sufficient active sites. However, ReSe2 has intrinsically poor conductivity, which leads to the insufficient utilization of electrocatalytic active sites. H...

Pressure has always been an effective method for uncovering novel phenomena and properties in condensed matter physics. Here, we carried out an electrical transport study on 2H-TaS2 up to ∼208 GPa, and found an unexpected superconducting state (SC-II) emerging around 86.1 GPa with an initial critical temperature (Tc) of 9.6 K. As pressure increases...

Recently, MoS2 has been considered as a promising economic and nontoxic thermoelectric material due to its low thermal conductivity and high Seebeck coefficient. However, the poor intrinsic electrical conductivity is still a main obstacle for its wide scale application. Here, we have successfully synthesized p-type V doped MoS2 and systematically i...

The discovery of Weyl and Dirac fermions has greatly encouraged the study of topological aspects in condensed matter physics, especially the discovery of ferromagnetic type-II Weyl semimetals such as CeAlX (X = Si, Ge). However, the evolution process of the physical characteristics of CeAlX during the Ge/Si substitution has not been studied in deta...

The exploration of efficient electrocatalysts for the hydrogen evolution reaction (HER) is beneficial to obtain renewable clean energy. Herein, a new parkerite-type compound Pt3Bi2S2 was synthesized, constructed by [PtBi4S2] octahedra. The Bi 6p orbital electrons upshift the Pt 5d band to promote hydrogen adsorption. Moreover, the Bi-Pt orbital hyb...

Exploring in-plane anisotropic 2D materials is of great significance to the fundamental studies and further development of polarizationsensitive optoelectronics. Herein, chiral niobium oxide diiodide (NbOI2) is introduced into the intriguing anisotropic 2D family with the experimental demonstration of anisotropic optical and electrical properties....

Topological superconductors (TSCs) are unconventional superconductors with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for quantum computation. Despite their importance in both fundamental research and applications, natural TSCs are very rare. Here, combining state of the art synchrotro...

2M−WS2 is a newly discovered superconductor with a rather high critical transition temperature (Tc=8.8K) and topological surface states. Recently Majorana bound states were observed in magnetic vortices of this material. Thus uncovering the flux dynamics of the magnetic vortices is essential to further promote the physical understanding and its pra...

Topological superconductors (TSCs) are unconventional superconductors with bulk superconducting gap and in-gap Majorana states on the boundary that may be used as topological qubits for quantum computation. Despite their importance in both fundamental research and applications, natural TSCs are very rare. Here, combining state of the art synchrotro...

High-pressure investigation has been shown to be of paramount significance for changing the conventional lattice or bringing fascinating properties, especially inducing superconducting phases. Here we studied the application of pressure to the recently synthesized 2M-WS2 with the record Tc (8.8 K) among transition metal dichalcogenides (TMDs) at am...

2 M WS2 is a newly discovered metastable transition metal dichalcogenide (TMDs) material with the highest instinct superconducting transition temperature (Tc) of 8.8 K among all TMDs superconductors. Here we report the structural regulation of 2 M WS2 by Se-doping and careful investigation on the doping effect on superconducting property. The resul...

Recently, a new transition-metal dichalcogenide (TMD) material 2M-phase WS2 was synthesized. The material 2M−WS2 not only exhibits superconductivity, with the highest Tc being 8.8 K at ambient pressure among TMDs, but also hosts a topological surface state. Here we report the low-temperature thermal conductivity measurements on 2M−WS2 single crysta...

1T'-phase transition metal dichalcogenides possess lots of intriguing physical properties including superconductivity, large magnetoresistance and topological surface state. Here, we investigated the electrical transport properties of 2M WSe2, which is constructed by 1T' WSe2 layers. We found that the 2M WSe2 has a high carrier mobility of 2.5 × 10...

Chevrel-phase superconducting compounds A y Mo6Q8 (A = Pb, Mg, etc. and Q = S, Se, Te) have attracted much attention due to their ultrahigh upper critical magnetic fields (Hc2). However, the binary compounds Mo6S8 and Mo6Te8 show no superconducting properties above 2 K. In this work, the new Chevrel-phase pseudobinary compound Mo6S6.8Te1.2 with a s...

Nitrogen doping strategy was adopted to improve the superconductivity of Mo2C for raising Fermi surface, yet it is difficult to prepare Mo2C with high nitrogen content. The highest doping content in the literature is only 1.36%, plus the preparation process is complex. In this work, a series of Mo2C1-xNx solid solution (x ≤ 0.57) was prepared by si...

This work reports the synthesis of a new quasi two-dimensional layered compound, K0.36(H2O) y WS2, for aqueous potassium ion storage. Its crystal structure determined by single crystal X-ray diffraction is composed of WS2 layers and disordered hydrated K+ stacking along the c direction alternately. Due to the large interlayer spacing and high condu...

Searching for Majorana bound states has become an important topic because of its potential applications in topological quantum computing. 2M-phase WS2, a newly synthesized superconductor, not only presents the highest superconducting transition temperature (Tc = 8.8 K) among the intrinsic transition metal dichalcogenides but also is predicted to be...

Recently, metastable polymorphs of MoS2 (1T, 1T’, 1T‴) have raised much attention due to their rich crystal structures and intriguing physicochemical properties. They are often derived from alkali metal intercalated compounds of MoS2, Ax(H2O)yMoS2 (A = alkali metal), by topotactic reaction. In order to make clear the deintercalation process, it is...

Electrolyte gating has been employed as an effective way to modulate the electronic properties of transition metal dichalcogenides (TMDs) by carrier doping over a wide range. Here, the carrier density of a new metastable phase of TMD material 2M‐WS2 is controlled by electrolyte gating to achieve reversible transitions between the superconducting st...

In this communication, we reported a new-phase 2M WSe 2 with a monoclinic space group C2/m. 2M WSe 2 presents a metallic behavior under ambient pressure and shows superconducting transition with a...

Rb0.21(H2O)yWS2, rubidium hydrate di­thio­tungstate, is a new quasi two-dimensional sulfide. Its crystal structure consists of ordered WS2 layers, separated by disordered Rb⁺ ions and water mol­ecules. All atomic sites are located on mirror planes. The WS2 layers are composed of edge-sharing [WS6] octa­hedra and extend parallel to (001). The presen...

Recently the metastable 1T′‐type VIB‐group transition metal dichalcogenides (TMDs) have attracted extensive attention due to their rich and intriguing physical properties, including superconductivity, valleytronics physics, and topological physics. Here, a new layered WS2 dubbed “2M” WS2, is constructed from 1T′ WS2 monolayers, is synthesized. Its...

Noncentrosymmetric MoS2 semiconductors (1H, 3R) possess not only novel electronic structures of spin-orbit coupling (SOC) and valley polarization but also remarkable nonlinear optical effects. A more interesting noncentrosymmetric struc-ture - the so-called 1T’’’-MoS2 layers was predicted to be built up from [MoS6] octahedral motifs by theoretician...

Transition-metal dichalcogenides open novel opportunities for the exploration of exciting new physics and devices. As a representative system, 2H-MoS2 has been extensively investigated owing to its unique band structure with a large band gap, degenerate valleys, and nonzero Berry curvature. However, experimental studies of metastable 1T polytypes h...

Urchin-like Mo2S3 crystals, prepared by a molten salt assisted solid-state method, have been explored as novel electro-catalysts for hydrogen evolution reactions for the first time. Because of their unique three-dimensional...

The interest in metastable MoS2 has been growing during the last five years. In the Review on page 15942 ff. F. Q. Huang et al. summarize the crystal phase and band structure of metastable polytypes and also the recent progress on the synthetic approaches and the uncovered intriguing physical properties. Although encouraging achievements are obtain...

Transition-metal dichalcogenides open novel opportunities for the exploration of exciting new physics and devices. As a representative system, 2H-MoS$_2$ has been extensively investigated owing to its unique band structure with a large band gap, degenerate valleys and non-zero Berry curvature. However, experimental studies of metastable 1T polytype...

Recently intriguing physics of superconductivity, type-II Weyl semimetal or quantum spin Hall states was discovered in metastable 1T'-type VIB-group transition metal dichalcogenides (TMDs). Even the topological superconductivity can be induced if the superconductivity and nontrivial topology coexist in this type of materials. Here, we report 2M WS2...

The 2H molybdenum disulfide (MoS2), as a stable hexagonal phase, has been one of the most studied transition metal dichalcogenides over the past decades. In the last five years, the metastable phases of MoS2 (1T, 1T', 1T'', and 1T''') have been revival of interests. Different from the edge‐sharing [MoS6] trigonal prisms in the 2H MoS2 phase, these...

2H MoS2 has been intensively studied because of layer-dependent electronic structures and novel physical properties. Though the metastable 1T MoS2 with the [MoS6] octahedron was observed from the microscopic area, the true crystal structure of 1T phase has not been determined strictly. Moreover, the true physical properties have not been demonstrat...

2H MoS2 has been intensively studied because of layer-dependent electronic structures and novel physical properties. Though the metastable 1T MoS2 with the [MoS6] octahedron was observed from the microscopic area, the true crystal structure of 1T phase has not been determined strictly. Moreover, the true physical properties have not been demonstrat...