Condensed matter systems can host quasiparticle excitations that are analogues to elementary particles such as Majorana, Weyl, and Dirac fermions. Recent advances in band theory have expanded the classification of fermions in crystals, and revealed crystal symmetry-protected electron excitations that have no high-energy counterparts.Here, using angle-resolved photoemission spectroscopy, we demonstrate the existence of a triply degenerate point in the electronic structure of MoP crystal, where the quasiparticle excitations are beyond the Majorana-Weyl-Dirac classification.Furthermore, we observe pairs of Weyl points in the bulk electronic structure coexisting with the 'new fermions', thus introducing a platform for studying the interplay between different types of fermions.In quantum field theory, Lorentz invariance gives three types of fermions, namely, the Dirac, Weyl and Majorana fermions (1,2). While it is still under debate whether any elementary particle of Weyl or Majorana types exists, all three types of fermions have been proposed to exist as low-energy and long-wavelength quasiparticle excitations in condensed matter systems (3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14). The existence of Dirac and Weyl fermions has been experimentally confirmed (15)(16)(17)(18)(19)(20) and that of Majorana fermions has been supported by various experiments (21,22). Recently, it has been shown theoretically that as the Poincare group (Lorentz group plus 4-translation) in the continuum space-time is reduced to the 230 space groups in lattices, more types of fermions (dubbed 'new fermions') are allowed to appear as quasiparticle excitations near certain band crossing points (23-29).Specially, it is well known that fermion statistics is incompatible with three-fold degeneracy in the continuum due to the half-integer spin; yet, three-fold degeneracy (triply degenerate point (TP)) can be protected in a lattice either by rotation symmetries (25-29) or nonsymmorphic symmetries (23,24). In either case, the three-component fermions conceptually lie between Weyl fermions (two-component) and Dirac fermions (four-component) (Fig. 1A), and carry characteristic properties distinct from the other two, including unique surface states and transport features. The crossing point is triply degenerate and protected by the C 3 symmetry along Γ-A, which is similar to the case of the Dirac semimetals Na 3 Bi (7) and Cd 3 As 2 (9). With SOC considered, the bands along Γ-A are reconstructed into two doubly-degenerate |J z | = 1/2 bands and two non-degenerate |J z | = 3/2 bands due to the M z mirror symmetry. The crossing points of the bands with different |J z | are protected by the C 3 symmetry, forming four TPs along the Γ-A line (Fig. 1F).We first perform core level photoemission measurements, which confirms the chemical composition of MoP ( Fig. 2A). respectively. We observe one hexagonal hole pocket around Γ and one small hole pocket at K at k z = 0, as well as one almost circular electron pocket around Α at k z = π.These experimental...

For use in high-magnetic-field coil-based applications, the critical current density (Jc) of REBa2Cu3Oy (REBCO, where RE = rare earth) coated conductors must be isotropically improved, with respect to the direction of the magnetic field; these improvements must be realized at the operating conditions of these applications. In this study, improvement of the Jc for various applied directions of magnetic field was achieved by controlling the morphology of the BaHfO3 (BHO) nano-rods in a SmBCO film. We fabricated the 3.0 vol. % BHO-doped SmBCO film at a low growth temperature of 720 °C, by using a seed layer technique (Ts = 720 °C film). The low-temperature growth resulted in a morphological change in the BHO nano-rods. In fact, a high number density of (3.1 ± 0.1) × 103 μm−2 of small (diameter: 4 ± 1 nm), discontinuous nano-rods that grew in various directions, was obtained. In Jc measurements, the Jc of the Ts = 720 °C film in all directions of the applied magnetic field was higher than that of the non-doped SmBCO film. The Jcmin (6.4 MA/cm2) of the former was more than 6 times higher than that (1.0 MA/cm2) of the latter at 40 K, under 3 T. The aforementioned results indicated that the discontinuous BHO nano-rods, which occurred with a high number density, exerted a 3D-like flux pinning at the measurement conditions considered. Moreover, at 4.2 K and under 17 T, a flux pinning force density of 1.6 TN/m3 was realized; this value was comparable to the highest value recorded, to date.

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PurposeVitamin C (VC) is a kind of essential nutrient in the body regarded as a canonical antioxidant during the past hundred years. However, the anti-cancer effect of VC is controversial. Our study is trying to clarify the relationship between VC dosage and breast cancer metastasis.MethodsHuman breast cancer cell lines Bcap37 and MDA-MB-453 were treated with VC at three different concentrations (low-dose, 0.01 mM; medium-dose, 0.1 mM; high-dose, 2 mM). Wound healing assays were conducted for migration assay; transwell tests were performed to detect the ability of cell invasion. The protein levels were evaluated by Western blot analysis or immunohistochemistry. Tumor xenografts in nude mice were built to test the effects of VC on breast cancer cell proliferation and metastasis.Results0.01 and 0.1 mM VC promoted cell migration and invasion when compared with the control group, but 2 mM VC significantly suppressed cell migration and invasion of breast cancer cell lines. High-dose VC increased E-cadherin and reduced Vimentin, indicating that high-dose VC suppressed epithelial-mesenchymal transition (EMT) in breast cancer cells. Besides, high-dose VC inhibited cell invasion promoted by TGF-β1 in breast cancer cells. Meanwhile, high-dose VC reversed the suppression of E-cadherin and enhancement of Vimentin induced by TGF-β1 in breast cancer cells. Furthermore, high-dose VC significantly inhibited breast cancer metastasis in vivo.ConclusionHigh-dose VC inhibits cell migration and invasion of breast cancer cell lines through suppressing EMT. Thus, it may be considered as an anticancer drug candidate for breast cancer patients.

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