nanosurface 2008-05-01 22:43
在纳米尺度材料上创建导电电路
【纳米科技世界快讯】"[i]自然：材料"[/i]杂志报道，研究人员发明了一种新方法，可以在纳米尺度的材料上创建导电电路。他们在3月在线出版的《自然—材料学》（Nature Materials）期刊上说，考虑到这些电路的尺寸，新发现将导致超密集信息储存和处理器件的研制。
在实验中，Jeremy Levy和同事充分利用两块钙钛矿晶体绝缘薄膜的介面在适当环境下具有高导电性的特性，在原子力显微镜的针尖上施加高压，然后再用这一针尖在几个纳米的尺度范围内绘制能携带电子信息的电路。因此，这个针尖可看做一只原子力铅笔，能在介面所代表的写字板上绘制纳米电路.
（《自然—材料学》（Nature Materials），doi:10.1038/nmat2136，C. Cen，J. Levy）
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Nature Materials 7, 298 - 302 (2008)
Published online: 2 March 2008 | doi:10.1038/nmat2136
Nanoscale control of an interfacial metal–insulator transition at room temperature
C. Cen1, S. Thiel2, G. Hammerl2, C. W. Schneider2, K. E. Andersen3, C. S. Hellberg3, J. Mannhart2 & J. Levy1
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Experimental1, 2, 3, 4, 5, 6, 7 and theoretical8, 9 investigations have demonstrated that a quasi-two-dimensional electron gas (q-2DEG) can form at the interface between two insulators: non-polar SrTiO3 and polar LaTiO3 (ref. 2), LaAlO3 (refs 3–5), KTaO3 (ref. 7) or LaVO3 (ref. 6). Electronically, the situation is analogous to the q-2DEGs formed in semiconductor heterostructures by modulation doping. LaAlO3/SrTiO3 heterostructures have recently been shown10 to exhibit a hysteretic electric-field-induced metal–insulator quantum phase transition for LaAlO3 thicknesses of 3 unit cells. Here, we report the creation and erasure of nanoscale conducting regions at the interface between two insulating oxides, LaAlO3 and SrTiO3. Using voltages applied by a conducting atomic force microscope (AFM) probe, the buried LaAlO3/SrTiO3 interface is locally and reversibly switched between insulating and conducting states. Persistent field effects are observed using the AFM probe as a gate. Patterning of conducting lines with widths of approx3 nm, as well as arrays of conducting islands with densities >1014 inch- 2, is demonstrated. The patterned structures are stable for >24 h at room temperature.
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1. Department of Physics and Astronomy, University of Pittsburgh, 3941 O'Hara St., Pittsburgh, Pennsylvania 15260, USA
2. Experimental Physics VI, Center for Electronic Correlations and Magnetism, Institute of Physics, University of Augsburg, D-86135, Augsburg, Germany
3. Center for Computational Materials Science, Naval Research Laboratory, Washington, DC 20375, USA
Correspondence to: J. Levy1 e-mail: [email]jlevy@pitt.edu[/email]
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