Browsing by Author "Xu, Peng"

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    Hybrid Molecular Beam Epitaxy of Complex Oxide Heterostructures with Ultrahigh Electron Density
    (2017-01) Xu, Peng
    Two-dimensional electron gases (2DEG) at complex oxide interfaces have attracted lots of attention for fundamental physics studies and potential applications in novel oxidebased electronics. While most researches focuses on LaAlO3/SrTiO3 heterostructures, many interesting phenomena were also discovered at titanates heterostructures, such as LaTiO3/SrTIO3 and GdTiO3/SrTiO3. In this study, we chose another material system, NdTiO3/SrTiO3, to investigate the 2DEG at the interfaces. NdTiO3 and SrTiO3 thin films and heterostructures were grown using the hybrid molecular beam epitaxy approach. 3E14 cm-2 (0.5 e-/u.c.) was realized at NdTiO3/SrTiO3 interfaces, and precise control of carrier density and metal-to-insulator transition were achieved by intentionally introducing Nd vacancies. Moreover, ultrahigh carrier density (~1E15 cm-2) was discovered by band engineering NdTiO3/SrTiO3 heterostructures. The charge transfer model was proposed to explain such high carrier density. Both experimental results and computational modeling suggest the broken-gap type band offset drives charge transfer from NdTiO3 to SrTiO3. Finally, we will also discuss environmental oxygen effects on electronic transport properties of NdTiO3/SrTiO3.
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    Places and Networks: The Changing Landscape of Transportation and Technology Final Summary Report of the STAR–TEA 21 Project
    (University of Minnesota Center for Transportation Studies, 2008-12) Berndt, Mark; Bolan, Richard S.; Burkhard, Richard; Douma, Frank; Duncan, Chandler; Handy, Susan L.; Horan, Thomas A.; Johnson, Andrew; Kaplancali, Ugur; Karamalaputi, Ramachandra; Kokotovich, Adam; Krizek, Kevin J.; Lehnhoff, James; Levinson, David; Li, Yi; Marich, Michael; McCabe, Denise; Munich, Lee W. Jr.; Parthasarathi, Pavithra; Schooley, Benjamin; Sullivan, Colbey; Wilson, Ryan; Xu, Peng; Yerra, Bhanu M.; Zhang, Lei
    Over the past six years, researchers from the University of Minnesota have studied the many ways in which transportation and technology intersect. Our work has explored these intersections from many perspectives, from ways intelligent transportation systems can help police, ambulance, and other public safety providers communicate more accurately and save lives, to the use of agent-based modeling to predict how high-technology workers will influence city form--and therefore, transportation needs--through their choices about work and home location. Two other areas of study are whether and how the Internet will replace travel demand and the potential loss of privacy related to advanced transportation technologies and the public policy issues surrounding privacy.