Catálogo de publicaciones - revistas

<jats:title>Abstract</jats:title> <jats:p>Electromagnetic metasurface with chaos patterned surface could bring rich interaction modes contributing to fully disordered random motions in deterministic systems, which preform uncertainty, irreducibility and unpredictability. In this paper, the influence of the correlation function (CF) properties of surface random patterns on the wave absorption performance is investigated. Complicated correlation function provides a fully developed random state, broadening the absorption bandwidth significantly and is helpful for reaching higher absorption rate. With the increase of the number of peaks in the correlation function, the absorption band at -15dB reflectivity widens significantly, band at -20dB reflectivity begins to emerge. As the first peak’s distance from original point in CF is enlarged, the absorption trough is gradually formed and deepened to -35dB level. The results give in-depth understanding of the relation between absorption behavior and controlling parameters including correlation, image information and foam spacer layer thickness. This high absorption absorber has great application potential in customizable radio communication compatibility device and anechoic testing chamber.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>For conductors in the ballistic regime, electron-boundary scattering at the sample edge plays a dominant role in determining the transport performance, giving rise to many intriguing phenomena like low-field negative magnetoresistance effect. In this study, we systematically investigate the magneto-transport behaviors of BN-encapsulated graphene devices with narrow channel width <jats:italic>W</jats:italic>, wherein the bulk mean free path <jats:italic>L</jats:italic> <jats:sub>mfp</jats:sub> can be very large and highly-tunable. By comparing the magnetoresistance features and the amplitude of <jats:italic>L</jats:italic> <jats:sub>mfp</jats:sub> in a large parameter space of temperature and carrier density, we reveal that the boundary-scattering-dominated negative magnetoresistance effect can still survive even when the ballistic ratio (<jats:italic>L</jats:italic> <jats:sub>mfp</jats:sub>/<jats:italic>W</jats:italic>) is as low as 0.15. This striking value is much smaller than the expected value for achieving (quasi-) ballistic transport regime (<jats:italic>L</jats:italic> <jats:sub>mfp</jats:sub>/<jats:italic>W</jats:italic> ≥ 1), and can be attributed to the ultra-low specularity of the sample edge of our graphene devices. These findings enrich our understanding of the effects of boundary scattering on channel transport, which is of vital importance for the future design of two-dimensional electronic devices with limited lateral size.</jats:p>

<jats:title>Abstract</jats:title> <jats:p>We predict that the square lattice layer formed by [Co$_2$N$_2$]$^{2-}$ diamond-like units can host high temperature superconductivity. The layer appears in the stable ternary cobalt nitride, BaCo$_2$N$_2$. The electronic physics of the material stems from Co$_2$N$_2$ layers where the dimerized Co pairs form a square lattice. The low energy physics near Fermi energy can be described by an effective two orbital model. Without considering interlayer couplings, the two orbitals are effectively decoupled. This electronic structure satisfies the "gene" character proposed for unconventional high temperature superconductors. We predict that the leading superconducting pairing instability is driven from an extended $s$-wave (s$^\pm$) to a $d$-wave by hole doping, for example in Ba$_{1-x}$K$_x$Co$_2$N$_2$. %In the transitional region, the material can host a mixed superconducting state such as d+is. This study provides a new platform to establish the superconducting mechanism of unconventional high temperature superconductivity.</jats:p>