We grow nearly freestanding single-layer 1T'-WTe2 on graphitized 6H-SiC(0001) by using molecular beam epitaxy (MBE), and characterize its electronic structure with scanning tunneling microscopy / spectroscopy (STM/STS). demonstrate the existence of topological edge states at periphery WTe2 islands. Surprisingly, we also find a band gap in bulk semiconducting behaviors low temperature, which is likely resulted from an incommensurate charge density wave (CDW) transition. The realization...

Atomically thin two-dimensional (2D) crystals have gained tremendous attentions owing to their potential impacts the future electronics technologies, as well exotic phenomena emerging in these materials. Monolayer of {\alpha} phase Sb ({\alpha}-antimonene) that shares same puckered structure black phosphorous, has been predicted be stable with precious properties. However, experimental realization still remains challenging. Here, we successfully grow high-quality monolayer...

Abstract Blue phosphorene (BlueP), a theoretically proposed phosphorous allotrope with buckled honeycomb lattice, has attracted considerable interest due to its intriguing properties. Introducing chirality into BlueP can further enrich physical and chemical properties, expanding potential for applications. However, the synthesis of chiral remains elusive. Here, we demonstrate growth large-area films on Cu(111), lateral size limited by wafer dimensions. Importantly, discovered that is...

Abstract The two-dimensional topological insulators host a full gap in the bulk band, induced by spin–orbit coupling (SOC) effect, together with topologically protected gapless edge states. However, it is usually challenging to suppress conductance and thus realize quantum spin Hall (QSH) effect. In this study, we find mechanism effectively conductance. By using quasiparticle interference technique scanning tunneling spectroscopy, demonstrate that QSH candidate single-layer 1 T ’-WTe 2 has...

Conformational arrangements in polymers on surfaces determine the overall shape as well potential properties. It is generally believed that conformational diversity leads to uncontrollable or disordered structures on-surface synthesis. However, this study, we obtain two well-ordered self-assembled covalently linked wavy chains with site-selective switching via Ullmann reaction of 1,2-bis(3-bromophenyl)ethane multiple conformations Ag(111). Two kinds exhibit distinct arrangements, where chain...

Black phosphorus (BP) has recently attracted considerable attention due to its unique structure and fascinating optical electronic properties as well possible applications in photothermal agents. However, main drawback is rapid degradation ambient environments of H2O O2, which led much research on the improvement stability. Unfortunately, this not shown great carrier mobilities. Here, we perform scanning tunneling microscopy observations few-layer BP (FLBP) sheets exfoliated ultrahigh vacuum...

Magnetic molecules on surfaces have been widely investigated to reveal delicate interfacial couplings and for potential technological applications. In these endeavors, one prevailing challenge is how preserve or recover the molecular spins, especially highly metallic substrates that can readily quench magnetic moments of ad-molecules. Here we use scanning tunneling microscopy/spectroscopy exploit semimetallic nature antimony observe, surprisingly yet pleasantly, spin Co-phthalocyanine well...

Achieving highly crystalline superconductors with reduced dimensionality and fine-tuning their superconductivity have been daunting challenges in condensed matter physics. Here, we successfully grown two-monolayer ${\mathrm{Pb}}_{1\ensuremath{-}x}{\mathrm{Bi}}_{x}$(111) films controllable Bi concentrations $x$ by molecular beam epitaxy systematically studied structural superconducting properties scanning tunneling microscopy. We first show that the transition temperatures of...

Surface reactivity is important in modifying the physical and chemical properties of surface-sensitive materials, such as topological insulators. Even though many studies addressing insulators towards external gases have been reported, it still under heavy debate whether how react with ${\mathrm{H}}_{2}\mathrm{O}$. Here, we employ scanning tunneling microscopy to directly probe surface reaction $\mathrm{B}{\mathrm{i}}_{2}\mathrm{T}{\mathrm{e}}_{3}$ Surprisingly, found that only top quintuple...

Fabrication of isostructural isovalent alloys is a powerful approach to discovering novel materials with emergent properties. This has been well established in traditional bulk materials, yet remains be fully exploited two-dimensional systems. Here we use black- phosphorus (BP)-like group-VA binary alloyed monolayers on BP-like group IV-VI substrates demonstrate the enabling power isomorphism and isovalency fabricating tunable We achieve formation nearly freestanding...

In article number 1806130, Wenguang Zhu, Shao-Chun Li, and co-workers describe the fabrication of monolayer α-phase antimonene, a structural analog to black phosphorous, on WTe2 substrate by molecular beam epitaxy. The α-antimonene exhibits great stability upon exposure air. Its electron band, crossing Fermi level, linear dispersion with fairly small effective mass, thus, good electrical conductivity. All these properties make promising for future electronic applications.

Quantum corrections to conductivity, which reflect charge carriers' quantum behavior, are a significant topic in condensed state physics and device design. A resistivity upturn at low temperature or weak antilocalization due has been often observed experimentally. However, the coexistence of low-temperature from bulk single crystals is seldom reported. Here, we report transport properties Ta1.04Ru0.78Te4 crystals. The samples showed metallic behavior with below ∼8.6 K, may be result...

The extreme magnetoresistance (XMR) of some compounds, challenging our understanding magnetoresistance, is an interesting topic in condensed-matter and materials physics future device applications. Here, we reported magnetotransport magnetic properties the as-grown post-annealed TaCo2Te2 single crystals. resistivity evolution with temperature two crystals shows a metallic behavior. Below 50 K, XMR effect for found, MR values at 3 K under 9 T are about 3.72 × 103% 5.71 102% annealed samples,...

Anomalous Hall effect, an interesting transport behavior, is of importance topic for fundamental physics and device application. Recently, the sign change anomalous effect (AHE) in some materials has being concerned. Here, we study electrical transport, magnetic properties, AHE Cr2.63V0.25Te4 single crystals. shows a bad metal behavior with resistivity kink at 178 K, corresponding to peak on heat capacity–temperature curve, strong electron correlation should be dominant mechanism below K. At...

Ta2Pd3Te5 has been recently identified as a van der Waals topological crystalline insulator candidate, but its magnetotransport properties are not reported. Here, we study electrical transport of single crystals. shows an insulating behavior with trend saturation below 20 K. The activity energy determined from the fits to polaron hopping model is Ea ∼ 36.1 meV, close value 42 meV previous scanning tunneling microscopy measurement. linear Hall resistivity negative slope suggests n-type...

Centrosymmetric ferro/ferrimagnets provide an ideal arena for fundamental research due to their fascinating magnetic and structural characters. In this work, the Co0.8MnSn compound with a single hexagonal phase was successfully synthesized, transition electronic properties have been systematically investigated. Interestingly, Arrott plots normalized entropy changes derived from isothermal magnetizing curves may imply first-order nature of ordering around TC ∼ 121 K. The AC susceptibility...

Lead iodide (PbI2), a typical layered semiconductor material, holds wide visible band gap and thickness-dependent structure, which can be widely used in optical devices perovskite solar cells. Although lead is one of the most extensively studied materials, there still lack experimental investigation electrical structure. In this study, we successfully grow PbI2 monolayer on highly oriented pyrolytic graphite (HOPG) substrate by molecular beam epitaxy (MBE). Scanning tunneling microscopy...

Abstract Nonvolatile electric-field control of the unique physical characteristics topological insulators (TIs) is essential for fundamental research and development practical electronic devices. Electrically tunable transport properties through electrostatic gates have been extensively investigated. However, relatively weak volatile tunability limits its applications in spintronics. Here, we demonstrate nonvolatile Bi 2 Te 3 via constructing ferroelectric Rashba architectures, i.e., 2D...

Stanene has been predicted to be a two-dimensional topological insulator (2DTI). Its low-buckled atomic geometry and the enhanced spin-orbit coupling are expected cause prominent quantum spin hall (QSH) effect. However, most of experimentally grown stanene date displays metallic state without real gap, possibly due chemical with substrate stress applied by substrate. Here,we demonstrate an efficient way tuning buckling in open topologically nontrivial energy gap. Via growth kinetics, we...