In a hybrid system of topological insulator (TI)/superconductor (SC), the proximity-induced topological superconductivity is expected to appear at the interface. Here we propose and demonstrate that a TI/SC hybrid Bi2Te3/PdTe2 heterostructure serves as a platform for exploring topological superconductivity with various features: all made of tellurium compounds, epitaxial growth, and a small charge transfer interface. In the Bi2Te3/PdTe2 heterostructure films, we observe large nonreciprocal charge transport near the superconducting transition temperature under a transverse in-plane magnetic field. The observation indicates the interplay between the topological surface state and superconductivity, suggesting that the Bi2Te3/PdTe2 heterostructure is a candidate for a topological superconductor. Also observed is an unexpected sign reversal of the nonreciprocal coefficient when the in-plane magnetic field is slightly tilted toward the out-of-plane direction. The analysis reveals that the sign reversal occurs with the change of dominant vortex type, that is, the change from spontaneous vortices to external-field induced ones.

The effect of laziness in the group chase and escape problem is studied using a simple model. The laziness is introduced as random walks in two ways: uniformly and in a "division of labor way. It is shown that, while the former is always ineffective, the latter can improve the efficiency of catching, through the formation of pincer attack configuration by diligent and lazy chasers.

We have investigated the charge transport in thin films of correlated Dirac semimetal of perovskite CaIrO3 by measurements of resistivity and optical spectra. The semimetallic transport of either electron-type or hole-type carrier is observed in the strain-relaxed thin films. By controlling the strain relaxation via thermal annealing, the carrier density decreases in both n-type and p-type samples, while enhancing the carrier mobility up to 160 cm2 V−1 s−1 at an electron density of 2.5 × 1018 cm−3 at 2 K. We propose that the energy of Dirac line node, which locates in proximity to the Fermi level, varies with the lattice distortion or strain-sensitive defect character, causing the sign change in the charge carrier as well as the mobility enhancement.

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