arXiv subjects

Zhiming Wang

Publications and source records attributed to Zhiming Wang.

94 records · Page 6Linked to original sources

arXiv2012

Ordered Array of Single Au Adatoms with Remarkable Thermal Stability: Au/Fe3O4(001)

We present a Scanning Tunneling Microscopy (STM) investigation of gold deposited at the magnetite Fe3O4(001) surface at room temperature. This surface forms a reconstruction with (\surd2\times\surd2)R45° symmetry, where pairs of Fe and neighboring O ions are slightly displaced laterally, forming undulating rows with 'narrow' and 'wide' adsorption sites. At fractional monolayer coverages, single Au adatoms adsorb exclusively at the narrow sites, with no significant sintering up to annealing temperatures of 400 °C. The strong preference for this site is possibly related to charge and orbital ordering within the first subsurface layer of the reconstructed Fe3O4(001) surface. Because of their high thermal stability, the ordered Au atoms at Fe3O4(001)- (\surd2\times\surd2)R45° could provide useful for probing the chemical reactivity of single atomic species.

cond-mat.mtrl-sci↗

arXiv2011

Reversible Transition Between Thermodynamically Stable Phases with Low Density of Oxygen Vacancies on SrTiO$_3$(110) Surface

The surface reconstruction of SrTiO$_3$(110) is studied with scanning tunneling microscopy and density functional theory (DFT) calculations. The reversible phase transition between (4$\times$1) and (5$\times$1) is controlled by adjusting the surface metal concentration [Sr] or [Ti]. Resolving the atomic structures of the surface, DFT calculations verify that the phase stability changes upon the chemical potential of Sr or Ti. Particularly, the density of oxygen vacancies is low on the thermodynamically stabilized SrTiO$_3$(110) surface.

cond-mat.mtrl-sci↗

arXiv2010

Evolution of the Surface Structures on SrTiO$_3$(110) Tuned by Ti or Sr Concentration

The surface structure of the SrTiO$_3$(110) polar surface is studied by scanning tunneling microscopy and X-ray photoelectron spectroscopy. Monophased reconstructions in (5$\times$1), (4$\times$1), (2$\times$8), and (6$\times$8) are obtained, respectively, and the evolution between these phases can be tuned reversibly by adjusting the Ar$^{+}$ sputtering dose or the amount of Sr/Ti evaporation. Upon annealing, the surface reaches the thermodynamic equilibrium that is determined by the surface metal concentration. The different electronic structures and absorption behaviors of the surface with different reconstructions are investigated.

cond-mat.mtrl-sci↗

arXiv2008

Electronic Conductivity Upturn of HOPG Contrast to Transport Properties of Polycrystal Graphite

The transport properties of highly oriented pyrolitic graphite (HOPG) and polycrystal graphite have been studied. The electric conductivity of HOPG is several times larger than that of the polycrystal graphite. Along with the large magnetoresistances (MR), the polycrystal graphite show the accordant semiconductor-like character in a wide temperature (roughly range from 20K to 120K) under 0, 4, 8, 12 T applied magnetic field, while the magnetic-field-induced metal-semiconductor-like transition was only found in HOPG. The difference of transport properties originates from the Coulomb interaction quasipartical in HOPG graphite layers in contrast with the grain boundary scattering in the polycrystal graphite.

cond-mat.mtrl-sci↗