Second-order topological insulators are crystalline with a gapped bulk and boundaries, but topologically protected gapless states at the intersection of two boundaries. Without further spatial symmetries, five ten Altland-Zirnbauer symmetry classes allow for existence such second-order in three dimensions. We show that reflection can be employed to systematically generate examples superconductors, although corners (in dimensions) or crystal edges continue exist if is broken. A...

A recent experiment [Nadj-Perge et al., Science 346, 602 (2014)] provides evidence for Majorana zero modes in iron (Fe) chains on the superconducting Pb(110) surface. Here, we study this system by scanning tunneling microscopy using tips. This high-resolution technique resolves a rich subgap structure, including zero-energy excitations some chains. We compare symmetry properties of data under voltage reversal against theoretical expectations and provide that putative signature overlaps with...

Ten isoindigo-based polymers were synthesized, and their photophysical electrochemical properties device performances systematically investigated. The HOMO levels of the tuned by introducing different donor units, yet all exhibited p-type semiconducting properties. hole mobilities these with centrosymmetric units exceeded 0.3 cm2 V–1 s–1, maximum reached 1.06 s–1. Because low-lying levels, copolymers also showed good stability upon moisture. AFM GIXD analyses revealed that symmetry backbone...

Graphene moiré superlattices show an abundance of correlated insulating, topological, and superconducting phases. Whereas the origins strong correlations nontrivial topology can be directly linked to flat bands, nature superconductivity remains enigmatic. We demonstrate that magic-angle devices made twisted tri-, quadri-, pentalayer graphene placed on monolayer tungsten diselenide exhibit flavor polarization superconductivity. also observe insulating states in tril- quadrilayer arising at...

The development of non-precious metal electrocatalysts for acidic oxygen evolution reaction (OER) that are highly durable, cost-effective, and efficient is crucial to advancing the use proton exchange membrane water electrolyzers (PEMWEs).

We combine scanning-tunneling-spectroscopy experiments probing magnetic impurities on a superconducting surface with theoretical analysis of the tunneling processes between (superconducting) tip and substrate. show that current through impurity-induced Shiba bound states is carried by single-electron at large tip-substrate distances Andreev reflections smaller distances. The requires relaxation processes, allowing us to extract information quasiparticle transitions lifetimes.

A recent experiment [Nadj-Perge et al, Science 346, 602 (2014)] gives possible evidence for Majorana bound states in chains of magnetic adatoms placed on a superconductor. While many features the observed end are naturally interpreted terms states, their strong localization remained puzzling. We consider linear chain Anderson impurities superconductor as minimal model and treat it largely analytically within mean-field theory. explore phase diagram, subgap excitation spectrum, wave...

Linear chains of magnetic atoms proximity coupled to an s-wave superconductor are predicted host Majorana zero modes at the chain ends in presence strong spin-orbit coupling. Specifically, iron (Fe) on Pb(110) have been explored as a possible system exhibit topological superconductivity and [ Nadj-Perge , S. et al., Science 2014 346 602 - 607 ]. Here, we study transition metal cobalt (Co) check for signatures. Using spin-polarized scanning tunneling spectroscopy, resolve ferromagnetic order...

Topological insulators and superconductors are characterized by their gapless boundary modes. In this paper, we develop a recursive approach to the Green function, which encodes nontrivial physics. Our describes various topologically trivial phases as fixed points of recursion provides direct access phase diagram, localization properties edge modes, well topological indices. We illustrate our in context familiar models such Su-Schrieffer-Heeger model, Kitaev chain, model for Chern insulator....

We propose a systematic way of constructing Floquet second-order topological insulators (SOTIs) based on time-glide symmetry, nonsymmorphic space-time symmetry that is unique in systems. In particular, we are able to show the static enlarged Hamiltonian frequency domain acquires reflection which inherited from original system. As consequence, one can construct variety symmetric SOTIs using knowledge SOTIs. Moreover, only needs be implemented approximately practice, enhancing prospects...

We investigate the nature of Yu-Shiba-Rusinov (YSR) subgap states induced by single Manganese (Mn) atoms adsorbed on different surface orientations superconducting lead (Pb). Depending adsorption site, we detect a distinct number and characteristic patterns YSR around Mn atoms. suggest that inherit their properties from $d$-levels, which are split surrounding crystal field. The periodicity long-range oscillations allows us to identify dominant coupling d-states outer Fermi sheet two-band...

We propose a realization of chiral Majorana modes propagating on the hinges 3D antiferromagnetic topological insulator, which was recently theoretically predicted and experimentally confirmed in tetradymite-type ${\mathrm{MnBi}}_{2}{\mathrm{Te}}_{4}$-related ternary chalgogenides. These materials consist ferromagnetically ordered 2D layers, whose magnetization direction alternates between neighboring forming an order. Besides surfaces with magnetic gap, there also exist gapless single Dirac...

Developing low-cost, efficient, and robust nonprecious metal electrocatalysts for oxygen evolution reactions (OER) in acidic medium is the major challenge to realize application of proton exchange membrane water electrolyzer (PEM-WE). It well-known that transition carbides (TMCs) have Pt-like electronic structures catalytic behaviors. However, monometallic show ignored OER activities. Herein, we reported activity TMCs can be enhanced by constructing bimetallic (TiTaC2) fabricated through...

Abstract Owing to the faster kinetics and outstanding catalytic performance, spinel oxides are regarded as a potential non‐precious metal electrocatalyst for oxygen evolution reaction (OER). Regulation of geometrical structures is one most effective approaches enhancing their OER performance. However, more wide deep investigations remain because structural complexity oxides, example, how fill unoccupied octahedral interstices construct large number active sites boosting OER. Herein, iron...

Abstract The misuse of antibiotics leads to emergence drug‐resistant bacteria. Developing artificial nanozymes with high stability and excellent catalytic performance is desirable substitute for antibiotics, but still remains huge challenge. Herein, the study reports a new strategy cascaded enhanced peroxidase (POD) reaction driving antibacterial therapy via constructing 2D conjugated metal‐organic frameworks (MOFs) non coordination saturation as nanozyme. It demonstrated that Cu atom...

Quasiparticle poisoning and diabatic transitions may significantly narrow the window for experimental observation of $4\pi$-periodic $dc$ Josephson effect predicted topological junctions. Here, we show that switching current measurements provide accessible robust signatures superconductivity which persist in presence quasiparticle processes. Such access to phase-dependent subgap spectrum currents junction when incorporating it into an asymmetric SQUID together with a conventional large...

Magnetic adsorbates on superconductors induce local bound states within the superconducting gap. These Yu-Shiba-Rusinov (\YSR) decay slowly away from impurity compared to atomic orbitals, even in 3d bulk crystals. Here, we use scanning tunneling spectroscopy investigate their hybridization between two nearby magnetic Mn adatoms a Pb(001) surface. We observe that leads formation of symmetric and antisymmetric combinations \YSR states. how structure dimer wave functions energy splitting depend...

Floquet higher-order topological insulators and superconductors (HOTI/SCs) with an order-two space-time symmetry or antisymmetry are classified. This is achieved by considering unitary loops, whose nontrivial topology leads to the anomalous phases, subject a symmetry/antisymmetry. By mapping these loops static Hamiltonians crystalline symmetry/antisymmetry, one able obtain $K$ groups for thus complete classification of HOTI/SCs. Interestingly, we found that every symmetry/antisymmetry...

Spinel oxides are considered as promising low-cost non-precious metal electrocatalysts for oxygen evolution reaction (OER) due to their desirable catalytic activities and fast kinetics. However, a result of the structural complexity spinel oxides, systematic in-depth studies on enhancing OER performance remain inadequate. In particular, construction active sites regarding large number unoccupied octahedral interstices has not yet been explored. Herein, more with high constructed surface via...