Van der Waals heterostructures are comprised of stacked atomically thin two-dimensional crystals and serve as novel materials providing unprecedented properties. Here we review the state-of-the-art assembly techniques of van der Waals heterostructures and illustrate their potentials to develop various types of van der Waals heterostructures.
Searching for charged lepton flavour violating (cLFV) processes is a powerful tool to explore new physics beyond the standard model of particle physics. The motivation of this type of experiment is getting higher since new physics at much higher energy scale can be probed compared to the experiments at the energy frontier machine LHC where any sign of new physics has not been observed yet. The MEG experiment searches for the LFV decay of muon, μ+→e+γ with an unprecedented sensitivity, which is high enough to test the predictions by many of the well-motivated models of new physics. No sign of the μ+→e+γ decay was observed in the full dataset of the MEG experiment taken between 2009 and 2013, setting a thirty times more stringent constraint on the existence of this decay mode compared to the previous experiment. An upgraded experiment, MEG II, where ten times higher sensitivity is achievable using more intense muon beam and upgraded detectors with much better performance, is soon to begin.
The equation of state of the strong interaction is constructed at finite chemical potentials including net baryon, electric charge, and strangeness. Relativistic hydrodynamic simulations for high-energy nuclear collisions are performed using the equation of state to demonstrate that the description of particle production is improved.
At the surface of Fe (Se, Te), where topological superconductivity emerges, vortex cores are expected to host Majorana Fermions. Using a dilution-refrigerator STM, we have systematically examined a large number of vortices in Fe (Se, Te). We found that some vortices possess the Zero-energy Vortex Bound State (ZVBS) below 20 μeV, which suggests its Majorana bound state origin. However, we also found vortices without the ZVBS. Interestingly, emergence of the ZVBS is not related to the preexisting quenched disorders, and the fraction of vortices with the ZVBS decreases with increasing magnetic field, suggesting the importance of the inter-vortex interaction for the ZVBS formation. These results provide the necessary conditions to realize the ZVBS, leading a way to control of Majorana quasiparticles for future applications.