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Ti 2 Cu, TiCu and TiCu 4 were synthesized and their electrocatalytic activities for hydrogen evolution reaction (HER) were investigated. The hydrogen overpotential observed at 10 mA/ cm2 (η 10) followed the order Ti 2 Cu (η 10 = −215 mV) > TiCu (η 10 = −182 mV) > TiCu 4 (η 10 = −170 mV). The hydrogen adsorption energy (∆G Had) on Cu site of TiCu 4 is exergonic and close to optimal position (i.e. ∆G Had = 0). A synergistic effect was proposed to account for the excellent HER performance of these Ti Cu binary intermetallics compounds that could replace PGM and achieve Midas touch in the future. [Display omitted] • High purity of Ti 2 Cu, TiCu and TiCu 4 were synthesized by using rapid arc-melting technique. • Hydrogen evolution reaction (HER) study on Ti 2 Cu, TiCu and TiCu 4 in alkaline media. • HER activity of Ti 2 Cu, TiCu and TiCu 4 were explored by using density functional theory. • Synergistic effect for these Ti Cu binary intermetallics toward HER activity was discussed. [ABSTRACT FROM AUTHOR]

Magnetic metals deposited on graphene hold the key to applications in spintronics. Here, we present the results of Fe islands grown on graphene/SiC(0001) by molecular beam epitaxy, which are investigated by scanning tunneling microscopy. The two types of islands distinguished by flat or round tops are revealed, indicating bimodal growth of Fe. The atomic structures on the top surfaces of flat islands are also clearly resolved. Our results may improve the understanding of the mechanisms of metals deposited on graphene and pave the way for future spintronic applications of Fe/graphene systems. [ABSTRACT FROM AUTHOR]

Organic‐inorganic hybrid multifunctional materials have received significant attention due to their potential applications in smart devices such as phase‐change memory (PCM), resistive random‐access memory (ReRAM). Yet, devices application requires achieving a balance between fast switching speeds, long‐term stability, and high cycling endurance in materials still facing difficulties. Herein, we report two hybrid phase transition compounds: (CMQ)BiCl5(CMQ=Chloromethyl Quinuclidin‐3‐one) (1) and (FMQ)2SbBr5(FMQ=Fluoromethyl Quinuclidin‐3‐one) (2), both two compounds exhibit high phase transition temperature, dual‐stable behavior in dielectric during reversible phase transition process. Notably, 1 exhibit small dielectric change after multiple dielectric state switching. Furthermore, investigate the influence of halogen substitution (F to Cl) for compound properties, which show an Increasing transition temperature (9 K) and raising structural dimension (0D to 1D). Additionally, using first principles, analyze the electronic structure of 1 and find that it has a 3.4 eV wide bandgap, closing to GaN semiconductor (3.4 eV). This work provides a new insight into developing the next‐generation phase transition compounds and chemical modification enhances material performance. [ABSTRACT FROM AUTHOR]

The Mn-Bi-Te class of compounds are recently discovered topological insulators with broken time-reversal-symmetry, which host unique quantum anomalous Hall and axion insulator states. Their key characteristics are believed to be sufficiently understood by models in a single-particle picture. Here, we apply scanning tunneling microscopy to study the electronic properties of MnBi2Te4 and MnBi4Te7. Unexpectedly, our quasiparticle interference (QPI) results demonstrate that rotational symmetry of the crystal breaks, i.e. a nematic-like pattern arises, in certain energy range but persists in others. Moreover, our data in the presence of an external magnetic field rule out the possibility of the material magnetism as an origin of the C2 symmetric QPI pattern. This study reveals that the interaction in the Mn-Bi-Te class of topological materials may play an essential role in their electronic states, and thus opens a new path for investigating the interplay between wavefunction topology and symmetry breaking phases. [ABSTRACT FROM AUTHOR]

A sufficiently large supercurrent can close the energy gap in a superconductor and create gapless quasiparticles through the Doppler shift of quasiparticle energy caused by finite Cooper pair momentum. In this gapless superconducting state, zero-energy quasiparticles reside on a segment of the normal-state Fermi surface, whereas the remaining Fermi surface is still gapped. We use quasiparticle interference to image the field-controlled Fermi surface of bismuth telluride (Bi2Te3) thin films under proximity effect from the superconductor niobium diselenide (NbSe2). A small applied in-plane magnetic field induces a screening supercurrent, which leads to finite-momentum pairing on the topological surface states of Bi2Te3. We identify distinct interference patterns that indicate a gapless superconducting state with a segmented Fermi surface. Our results reveal the strong impact of finite Cooper pair momentum on the quasiparticle spectrum. [ABSTRACT FROM AUTHOR]

To realize the braiding operations of the Majorana zero modes in the vortex cores of a topological superconductor (TSC), a novel approach is proposed in this letter to replace the common tip (or tip-like) method. Instead of being on top of the TSC thin film, arrays of electrically controllable pinning centers are built beneath the film, hence detection can proceed along with braiding. This does not only increase the braiding rate, but also enables the braiding to be performed in an electrically controllable way and to be integrated into a large scale. Our work paves the way toward large-scale topological quantum computation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Monolayer C 60 film is grown on a SrTiO 3 (0 0 1) surface for the first time. • Monolayer C 60 exhibit a short-range ordered molecular arrangement, while multi-layer C 60 show a quasi-(2 × 2) superstructure with a chiral pinwheel motif. • Monolayer C 60 on STO shows the largest HOMO-LUMO gap comparing to those on any other substrates. Ultrathin fullerene (C 60) films on various metal and semiconductor substrates have been intensively studied but not yet on a perovskite oxide substrate. Using scanning tunneling microscopy and spectroscopy, we investigated the molecular arrangement and electronic structure of C 60 ultrathin films grown on a SrTiO 3 (0 0 1) surface. Subject to strong coupling and weak screening from the substrate, the monolayer C 60 exhibit short-range ordered molecular arrangement with disordered molecular orientation and a substantially large highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) gap (∼4.1 eV). In contrast, C 60 in the 2nd and 3rd layers are self-assembled into hexagon lattices with a quasi-(2 × 2) superstructure resulted from the arrangement of molecular orientations showing a chiral pinwheel structure. The HOMO-LUMO gap of the multi-layer C 60 further expands to ∼ 4.6 eV, very close to that of gas-phase C 60 , indicating a negligible inter-layer screening effect. [ABSTRACT FROM AUTHOR]