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Abstract Phase engineering is a breakthrough for various electronic and energy device applications with transition metal dichalcogenides (TMDs). Chemical methods, such as lithium intercalation, are mostly used for phase engineering, which achieves atomically thin flakes and high catalytic performances in several group 6 TMDs including MoS 2 . However, chemical methods cannot be applied to MoTe 2 , a widely investigated group 6 TMD with intriguing semiconducting, topological, and catalytic proper

Lattice distortion, spin interaction, and dimensional crossover in transition metal dichalcogenides (TMDs) have led to intriguing quantum phases such as charge density waves (CDWs) and 2D magnetism. However, the combined effect of many factors in TMDs, such as spin-orbit, electron-phonon, and electron-electron interactions, stabilizes a single quantum phase at a given temperature and pressure, which restricts original device operations with various quantum phases. Here, nontrivial polymorphic qu

Transition metal dichalcogenides (TMDs) have been investigated for use in a hydrogen evolution reaction (HER), mostly in the form of nano-sized flakes, due to the abundant active site formation by nanostructuring, surface functionalization, and phase engineering. However, the physical origin of the active HER on TMDs remains to be clarified. Here, we investigate the role of anion vacancies for the HER on the basal plane of single-crystalline tungsten dichalcogenide (WTe2), a group 6 metallic TMD

Abstract The phase engineering of transition metal dichalcogenides (TMDs) is considered a promising strategy for promoting efficient catalysis, such as the hydrogen evolution reaction (HER). While theoretical studies predict the presence of catalytically active atomic sites at heterophase boundaries in TMDs, conventional bulk HER measurements are not able to precisely explore these 1D heterophase regions for HER. Here, one reports on active HER occurring at heterophase boundaries between the sem

Monoclinic group 6 transition metal dichalcogenides (TMDs) have been extensively studied for their intriguing 2D physics (e.g. spin Hall insulator) as well as for ohmic homojunction contacts in 2D device applications. A critical prerequisite for those applications is thickness control of the monoclinic 2D materials, which allows subtle engineering of the topological states or electronic bandgaps. Local thickness control enables the realization of clean homojunctions between different electronic

We report the electrochemical hydrogen evolution reaction (HER) of two-dimensional metallic transition metal dichalcogenides (TMDs). TMTe2 (TM: Mo, W, and V) single crystals were synthesized and characterized by optical microscopy, X-ray diffraction, and electrochemical measurements. We found that TMTe2 acts as a HER-active catalyst due to the inherent catalytic activity of its basal planes. Among the three metallic TMTe2, VTe2 shows the best HER performance with an overpotential of 441 mV and a

Abstract Memory devices are an essential part of modern electronics. Efforts to move beyond the traditional “read” and “write” of digital information in volatile and non‐volatile memory devices are leading to the rapid growth of neuromorphic technology. There is a growing demand for memory devices with continuous memory states with various retention times and greater integration density with more energy‐efficient mechanisms. Two types of memory devices (i.e., non‐volatile digital memory and neur

Silver-based nanomaterials have been versatile building blocks of various photoassisted energy applications; however, they have demonstrated poor electrochemical catalytic performance and stability, in particular, in acidic environments. Here we report a stable and high-performance electrochemical catalyst of silver telluride (AgTe) for the hydrogen evolution reaction (HER), which was synthesized with a nanoporous structure by an electrochemical synthesis method. X-ray spectroscopy techniques on

Transition metal dichalcogenides (TMDs) are considered as promising catalysts for the hydrogen evolution reaction (HER) owing to their abundant active sites such as atomic vacancies and step edges. Moreover, TMDs have polymorphism, which has stimulated extensive studies on tuning of surface electronic structures for an active HER. The polymorphism in TMDs provides an opportunity for new hybrid catalysts with TMDs and other catalytic metals via surface engineering that can create a novel function

The tuning catalytic functionality of transition metal dichalcogenides (TMDs) with multi-dimensional defects, such as interfaces (2D), edges (1D), and atomic vacancies (0D), is currently considered a promising strategy for energy applications. The pristine edges and plasma-treated basal planes of various TMDs have been extensively studied for practical hydrogen evolution reaction (HER). Here, we demonstrate active HER on the plasma-treated edges of semimetallic layered tungsten ditellurides (WTe

Despite the remarkable electronic and mechanical properties of graphene, improving the catalytic activity of the atomically flat, inert, and stable carbon network remains a challenging issue in both fundamental and application studies. In particular, the adsorption of most molecules and ions, including hydrogen (H₂ or H⁺), on graphene is not favorable, underlining the challenge for an efficient electrochemical catalytic reaction on graphene. Various defects, edges, and func

Modulating semiconducting channel potential has been used for electrical switching in transistors without biological plasticity operations that are critical for energy-efficient neuromorphic computing. To achieve efficient data processing, alternative transport mechanisms, such as tunneling and thermionic emission, have been introduced with 2D materials. Here, a polymorphic memtransistor based on atomically thin Mo_0.91 W_0.09 Te₂ is presented, where the lattice an

Thermoelectric power, has been extensively studied in low-dimensional materials where quantum confinement and spin textures can largely modulate thermopower generation. In addition to classical and macroscopic values, thermopower also varies locally over a wide range of length scales, and is fundamentally linked to electron wave functions and phonon propagation. Various experimental methods for the quantum sensing of localized thermopower have been suggested, particularly based on scanning probe

We synthesized a series of slightly erbium-substituted yttrium iron garnets (Er:YIG), Y_3-<i>x</i> Er <i>_x</i> Fe₅O₁₂ at different Er concentrations (<i>x</i> = 0, 0.01, 0.05, 0.10, and 0.20) using a solid-state reaction and investigated their structural, magnetic, and optical properties as a function of Er concentration. The volume of the unit cell slightly increased with Er concentration and Er atoms predominately replaced Y atoms in the dodecahedrons