The Color Octet Effect from e+e−→J/ψ+X+γe^+ e^-\to{J/\psi}+X+\gamma at B Factory

We study the initial state radiation process $e^+ e^-\to{J/\psi}+X+\gamma$ for $J/\psi$ production at B factory, and find the cross section is 61% larger than it's Born one for color octet part and is about half as it's Born one for color singlet part. Furthermore, the color singlet and color octet signal are very clearly separated in it's $E_\gamma$ spectra due to kinematics difference. We suggest to measure this $E_\gamma$ spectra at B factory to determine the color octet effect.Comment: 4 pages, 4 figures and 1 tabl

STM studies of epitaxial graphene

This article reviews the use of scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS) to characterize the physical and electronic properties of epitaxial graphene. Topographical variations revealed by STM allow the determination of the number of graphene layers and the detection of lattice mismatch between the graphene and the substrate, as well as rotational disorder. STS allows the local electronic characterization of graphene. STM/STS can also be used to perform local studies of graphene modification through processes such as atomic/molecular adsorption and intercalation

Study of electromagnetic enhancement for surface enhanced Raman spectroscopy of SiC graphene

The electromagnetic enhancement for surface enhanced Raman spectroscopy (SERS) of graphene is studied by inserting a layer of Al 2O 3 between epitaxial graphene and Au nanoparticles. Different excitation lasers are utilized to study the relationship between laser wavelength and SERS. The theoretical calculation shows that the extinction spectrum of Au nanoparticles is modulated by the presence of graphene. The experimental results of the relationship between the excitation laser wavelength and the enhancement factor fit well with the calculated results. An exponential relationship is observed between the enhancement factor and the thickness of the spacer layer

Direct observation of two-dimensional small polarons at correlated oxide interface

Two-dimensional (2D) perovskite oxide interfaces are ideal systems where diverse emergent properties can be uncovered.The formation and modification of polaronic properties due to short-range strong charge-lattice interactions of 2D interfaces remains hugely intriguing.Here, we report the direct observation of small-polarons at the LaAlO3/SrTiO3 (LAO/STO) conducting interface using high-resolution spectroscopic ellipsometry.First-principles investigations further reveals that strong coupling between the interfacial electrons and the Ti-lattice result in the formation of localized 2D small polarons.These findings resolve the longstanding issue where the excess experimentally measured interfacial carrier density is significantly lower than theoretically predicted values.The charge-phonon induced lattice distortion further provides an analogue to the superconductive states in magic-angle twisted bilayer graphene attributed to the many-body correlations induced by broken periodic lattice symmetry.Our study sheds light on the multifaceted complexity of broken periodic lattice induced quasi-particle effects and its relationship with superconductivity