Usually, microelectronic devices are made of silicon1 or similar 百度竞价推广iconductors2. Recently, the electronic properties of metal oxides have become quite interesting. These materials are more complex, yet offer a broader range of possibilities to tune3 their properties. An important breakthrough has now been achieved at the Vienna University of Technology: a two dimensional electron gas was created in strontium titanate. In a thin layer just below the surface electrons can move freely and occupy different quantum states. Strontium titanate is not only a potential future alternative to standard 百度竞价推广iconductors, it could also exhibit interesting phenomena4, such as superconductivity, thermoelectricity（温差电学） or magnetic effects that do not occur in the materials that are used for todays electronic devices.The Surface Layer and the InsideThis project closely links theoretical calculations and experiments. Zhiming Wang from Professor Ulrike Diebolds research team was the leading experimentalist; some of the experimental work was done at the synchrotron（同步加速器） BESSY in Berlin. Zhicheng Zhong from Professor Karsten Helds group studied the material in computer simulations.Not all of the atoms of strontium titanate are arranged in the same pattern: if the material is cut at a certain angle, the atoms of the surface layer form a structure, which is different from the structure in the bulk of the material. Inside, every titanium atom has six neighbouring oxygen atoms, whereas the titanium atoms at the surface are only connected to four oxygen atoms each, says Ulrike Diebold. This is the reason for the remarkable5 chemical stability of the surface. Normally such materials are damaged if they come into contact with water or oxygen.
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1 silicon n.硅 参考例句： This company pioneered the use of silicon chip.这家公司开创了用硅片的办法。 A chip is a piece of silicon about the size of a postage stamp.芯片就是一枚邮票大小的硅片。
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