Magnetic Gap of Fe-Doped BiSbTe₂Se Bulk Single Crystals Detected by Tunneling Spectroscopy and Gate-Controlled Transports

Measurement of a sign-changing two-gap superconducting phase in electron-doped Ba(Fe(1-x)Co(x))2As2 single crystals using scanning tunneling spectroscopy.

Scanning tunneling spectroscopic studies of Ba(Fe(1-x)Co(x))(2)As(2) (x=0.06, 0.12) single crystals reveal direct evidence for predominantly two-gap superconductivity. These gaps decrease with increasing temperature and vanish above the superconducting transition T(c). The two-gap nature and the slightly doping- and energy-dependent quasiparticle scattering interferences near the wave vectors (...

Magnetic hysteresis and relaxation in Bi2212 single crystals doped with Fe and Pb

Magnetic hysteresis and magnetic relaxation measurements have been performed to study vortex pinning behaviors for pure, Fe doped and heavily Pb doped Bi2212 single crystals. Unlike pure and Fe doped Bi2212 crystals, heavily Pb doped crystal showed strong vortex pinning behavior. We interpret the strong pinning in heavily Pb doped Bi2212 single crystals as arising from the improved Josephson co...

Photoassisted Scanning Tunneling Microscopy and Tunneling Spectroscopy of n-Type Tungsten Diselenide (n- WSe2) Single Crystals

The van der Waals surface (perpendicular to the c axis) of a nondegenerate n-type WSe2 single crystal was imaged at negative substrate bias voltage (V) in the constant-current mode in air with a scanning tunneling microscope (STM) combined with optical excitation techniques. A current (i) image at a positive bias under steady-state illumination, obtained simultaneously with the topographic imag...

Scanning tunneling microscopy and tunneling spectroscopy of n-type iron pyrite (n-FeS2) single crystals

Direct observation of the single-domain limit of Fe nanomagnets by spin-polarized scanning tunneling spectroscopy.

We have investigated the magnetic structure of self-organized Fe islands on W(001) by means of spin-polarized scanning tunneling spectroscopy (Sp-STS). Single-domain, simple vortex, and distorted vortex states have been observed. The high resolution magnetic images were used to experimentally determine the single-domain limit. The experimental structures were compared with results of micromagne...