The electronic Fabry-Pérot interferometer operating in the quantum Hall regime may be a promising tool for probing edge state interferences and studying the non-Abelian statistics of fractionally charged quasiparticles. Here we report on realizing a quantum Hall Fabry-Pérot interferometer based on monolayer graphene. We observe resistance oscillations as a function of perpendicular magnetic field and gate voltage both on the electron and hole sides. Their Coulomb-dominated origin is revealed by the positive (negative) slope of the constant phase lines in the plane of magnetic field and gate voltage on the electron (hole) side. Our work demonstrates that the graphene interferometer is feasible and paves the way for the studies of edge state interferences since high-Landau-level and even denominator fractional quantum Hall states have been found in graphene.

Recently, the layered transition metal dichalcogenide 1T' MoTe2 has attracted considerable attention due to its non-saturating magnetoresistance, type-II Weyl semimetal properties, superconductivity, and potential candidate for two-dimensional (2D) topological insulator in the single-and few-layer limit. Here in this work, we perform systematic transport measurements on thin flakes of MoTe2 prepared by mechanical exfoliation. We find that MoTe2 flakes are superconducting and have an onset superconducting transition temperature Tc up to 5.3 K, which significantly exceeds that of its bulk counterpart. The in-plane upper critical field (Hc2||) is much higher than the Pauli paramagnetic limit, implying that the MoTe2 flakes have Zeeman-protected Ising superconductivity. Furthermore, the Tc and Hc2 can be tuned by up to 320 mK and 400 mT by applying a gate voltage. Our result indicates that MoTe2 flake is a good candidate for studying exotic superconductivity with nontrivial topological properties.

We systematically studied surface plasmons reflection by graphene wrinkles with different heights on SiC substrate. Combined with numerical simulation, we found that the geometry corrugation of a few nanometer height wrinkle alone does not causes a reflection of graphene plasmons. Instead, the separated wrinkle from substrate exhibits a nonlinear spatial Fermi energy distribution along the wrinkle, which acts as a heterojunction. Therefor a higher graphene wrinkle induces a stronger damped region when propagating graphene surface plasmons encounter the wrinkle and get reflected.

The quantum effect of nonlinear co-tunnelling process, which is dependent on atom-pair tunneling and asymmetry of an double-well trap, is studied by using an asymmetrical extended Bose-Hubbard model. Due to the existence of atom-pair tunneling that describes quantum phenomena of ultracold atom-gas clouds in an asymmetrical double-well trap, the asymmetrical extended Bose-Hubbard model is better than the previous Bose-Hubbard model model by comparing with the experimental data cited from the literature. The dependence of dynamics and quantum phase transition on atom-pair tunneling and asymmetry are investigated. Importantly, it shows that the asymmetry of the extended Bose-Hubbard model, corresponding to the bias between double wells, leads to a number of resonance tunneling processes, which tunneling is renamed conditional resonance tunneling, and corrects the atom-number parity effect by controlling the bias between double wells.

The interaction between extracellular matrices and cancer cells plays an important role in regulating cancer cell behaviors. In this article, we use matrigel to mimic extracellular matrices and investigate experimentally how matrigel influences the shape and dynamics of breast cancer cells (MDA-MB-231-GFP cells). We find that matrigel facilitates cancer cells' migration and shape deformation. The influences of the matrigel concentration are also reported.

We report robust superconducting state and gap symmetry of Nb₅Ir₃O via electrical transport and specific heat measurements. The analysis of specific heat manifests that Nb₅Ir₃O is a strongly coupled superconductor with ΔC/γ_nT_c~1.91 and double s-wave superconducting gaps of 2△_L(0)/k_BT_c~6.56 and 2△_S(0)/k_BT_c~2.36 accounting for 90% and 10%, respectively. The (C_p-γ_nT)/T³ vs. T plot shows a broad peak at~23 K, indicating phonon softening and the appearance of low-lying phonon mode associated with the interstitial oxygen. This behavior explains the monotonic increase of T_c in Nb₅Ir₃O_(1-δ) by strengthening the electron-phonon coupling and enlarging the density of states at Fermi level. The Hall coefficient is temperature independent below 200 K, and changes its sign from positive to negative above 250 K, suggesting that carrier is across the hole- to electron-dominant regions and the multi-band electronic structures. On warming, the resistivity shows a gradual crossover from T²- to T³-dependence at a critical temperature T^*, and a broad peak at a temperature T_p. The reduced T_c under pressure is linearly correlated with lattice parameters c/a ratio and T_p, suggesting the important phonon contributions in Nb₅Ir₃O as a phonon-medicated superconductor. Possible physical mechanisms are proposed.

Atomically thin transition metal dichalcogenide films with distorted trigonal (1T') phase have been predicted to be candidates for realizing quantum spin Hall effect. Growth of 1T' film and experimental investigation of its electronic structure are critical. Here we report the electronic structure of 1T'-MoTe₂ films grown by molecular beam epitaxy (MBE). Growth of the 1T'-MoTe₂ film depends critically on the substrate temperature, and successful growth of the film is indicated by streaky stripes in the reflection high energy electron diffraction (RHEED) and sharp diffraction spots in the low energy electron diffraction (LEED). Angle-resolved photoemission spectroscopy (ARPES) measurements reveal a metallic behavior in the as-grown film with an overlap between the conduction and valence bands. First principles calculation suggests that a suitable tensile strain along the a-axis direction is needed to induce a gap to make it an insulator. Our work not only reports the electronic structure of MBE grown 1T'-MoTe₂ films, but also provides insights for strain engineering to make it possible for quantum spin Hall effect.

Transition-metal chalcogenide nanowires (TMCN) as a viable candidate for nanoscale applications have been attracting much attention for the last few decades. Starting from the rigid building block of M₆ octahedra (M=transition metal), depending on the way of connection between M₆ and decoration by chalcogenide atoms, multiple types of extended TMCN nanowires can be constructed based on some basic rules of backbone construction proposed here. Note that the well-known Chevrel-phase based M₆X₆ and M₆X₉ (X=chalcogenide atom) nanowires, which are among our proposed structures, have been successfully synthesized by experiment and well studied. More interestingly, based on the construction principles, we predict three new structural phases (the cap, edge, and C&E phases) of Mo₅S₄, one of which (the edge phase) has been obtained by top-down electron beam lithography on two-dimensional MoS₂, and the C&E phase is yet to be synthesized but appears more stable than the edge phase. The stability of the new phases of Mo₅S₄ is further substantiated by crystal orbital overlapping population (COOP), phonon dispersion relation, and thermodynamic calculation. The barrier of the structural transition between different phases of Mo₅S₄ shows that it is very likely to realize an conversion from the experimentally achieved structure to the most stable C&E phase. The calculated electronic structure shows an interesting band nesting between valence and conduction bands of the C&E Mo₅S₄ phase, suggesting that such a nanowire structure can be well suitable for optoelectronic sensor applications.