Surface plasmon polaritons in topological insulator

We study surface plasmon polaritons on topological insulator-vacuum interface. When the time-reversal symmetry is broken due to ferromagnetic coupling, the surface states exhibit magneto-optical Kerr effect. This effect gives rise to a novel transverse type surface plasmon polariton, besides the longitudinal type. In specific, these two types contain three different channels, corresponding to the pole of determinant of Fresnel reflection matrix. All three channels of surface plasmon polaritons display tight confinement, long lifetime and show strong light-matter coupling with a dipole emitter.Comment: 6 pages, 4 figure

Complex Landau levels and related transport properties in the strained zigzag graphene nanoribbons

The real magnetic fields (MFs) acting on the graphene can induce flat real Landau levels (LLs). As an analogy, strains in graphene can produce significant pseudo MFs, triggering the appearance of dispersive pseudo LLs. By analysing the low energy effective Hamiltonian, we introduce the concept of the effective orbital MFs to integrate the real MFs and pseudo MFs. Accordingly, we obtain the complex LLs which incorporate the real LLs and pseudo LLs, and calculate the related transport properties. With the aid of these ideas, we reveal the mechanism underlying the fragility of the pseudo LLs against disorders, and predict that the $K$ and $K'$ valleys have different robust performances against the Anderson disorders and dephasing effects. Furthermore, the tunability of the polarized valley currents is also studied, opening up new possibilities for the design of valleytronics devices

Development of a time-to-digital converter ASIC for the upgrade of the ATLAS Monitored Drift Tube detector

The upgrade of the ATLAS muon spectrometer for high-luminosity LHC requires new trigger and readout electronics for the various elements of the detector. We present the design of a time-to-digital converter (TDC) ASIC prototype for the ATLAS Monitored Drift Tube (MDT) detector. The chip was fabricated in a GlobalFoundries 130 nm CMOS technology. Studies indicate that its timing and power consumption characteristics meet the design specifications, with a timing bin variation of 40 ps for all 48 channels with a power consumption of about 6.5 mW per channel.Comment: 9 pages, 12 figure