Nanoscale control of an interfacial metal-insulator transition at room temperature
Nanoscale control of an interfacial metal-insulator transition at room temperature
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DOI：
10.1038/nmat2136
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发表时间：
2008-03-01
期刊：
影响因子：
41.2
通讯作者：
Levy, J.
中科院分区：
文献类型：
--
作者：
Cen, C.;Thiel, S.;Levy, J.
实验（1-7）和理论（8，9）研究表明，准二维电子气（q-2DEG）可以在非极性SrTiO 3和极性LaTiO 3（参考文献2）、LaAlO 3（参考文献3-5）、KTaO 3（参考文献7）或LaVO 3（参考文献6）之间的界面处形成。在电子学上，这种情况类似于通过调制掺杂在半导体异质结构中形成的q-2DEG。LaAlO 3/SrTiO 3异质结构最近被证明（10），对于3个晶胞的LaAlO 3厚度，表现出滞后电场诱导的金属-绝缘体量子相变。在这里，我们报告的创建和擦除的纳米级导电区域之间的两个绝缘氧化物，LaAlO 3和SrTiO 3的界面。使用由导电原子力显微镜（AFM）探针施加的电压，掩埋的LaAlO 3/SrTiO 3界面局部和可逆地在绝缘和导电状态之间切换。使用AFM探针作为栅极观察到持续的场效应。展示了宽度类似于3 nm的导电线的图案化以及密度>10（14）英寸（-2）的导电岛的阵列。图案化结构在室温下稳定>24 h。
Experimental(1-7) and theoretical(8,9) 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 shown(10) 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 similar to 3 nm, as well as arrays of conducting islands with densities >10(14) inch(-2), is demonstrated. The patterned structures are stable for >24 h at room temperature.