Hydrostatic pressure response of an oxide-based two-dimensional electron system
Hydrostatic pressure response of an oxide-based two-dimensional electron system
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DOI：
10.1103/physrevb.93.235117
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发表时间：
2016-05
影响因子：
3.7
通讯作者：
J. Zabaleta;V. Borisov;R. Wanke;H. Jeschke;S. C. Parks;B. Baum;A. Teker;T. Harada;K. Syassen;T. Kopp;N. Pavlenko;N. Pavlenko;R. Valentí;J. Mannhart
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文献类型：
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作者：
J. Zabaleta;V. Borisov;R. Wanke;H. Jeschke;S. C. Parks;B. Baum;A. Teker;T. Harada;K. Syassen;T. Kopp;N. Pavlenko;N. Pavlenko;R. Valentí;J. Mannhart
具有令人着迷的特性的二维电子系统存在于多层标准半导体、氦表面和氧化物中。与半导体的二维 (2D) 电子气相比，氧化物中的 2D 电子系统通常具有更强的相关性，并且对主晶格的微观结构更敏感。这种敏感性表明氧化物 2D 系统可以通过静水压力进行高度调节。在这里，我们探讨了静水压力对 ${\mathrm{LaAlO}}_{3}\ensuremath{-}{\mathrm{SrTiO}}_{3}$ 界面形成的良好表征的二维电子系统的影响 [A. Ohtomo 和 H. Y. Hwang, Nature (London) 427, 423 (2004)] 并测量明显的、意想不到的响应。 $\ensuremath{\sim}2$ GPa 的压力可逆地将 4 K 时的二维载流子密度 ${n}_{s}$ 加倍。随着 ${n}_{s}$ 的增加，电导率和迁移率在压力下降低。第一原理压力模拟揭示了载流子密度的相同行为，并根据两种材料的介电特性及其在外部压力下的变化提出了迁移率降低的可能机制。
Two-dimensional electron systems with fascinating properties exist in multilayers of standard semiconductors, on helium surfaces, and in oxides. Compared to the two-dimensional (2D) electron gases of semiconductors, the 2D electron systems in oxides are typically more strongly correlated and more sensitive to the microscopic structure of the hosting lattice. This sensitivity suggests that the oxide 2D systems are highly tunable by hydrostatic pressure. Here we explore the effects of hydrostatic pressure on the well-characterized 2D electron system formed at ${\mathrm{LaAlO}}_{3}\ensuremath{-}{\mathrm{SrTiO}}_{3}$ interfaces [A. Ohtomo and H. Y. Hwang, Nature (London) 427, 423 (2004)] and measure a pronounced, unexpected response. Pressure of $\ensuremath{\sim}2$ GPa reversibly doubles the 2D carrier density ${n}_{s}$ at 4 K. Along with the increase of ${n}_{s}$, the conductivity and mobility are reduced under pressure. First-principles pressure simulations reveal the same behavior of the carrier density and suggest a possible mechanism of the mobility reduction, based on the dielectric properties of both materials and their variation under external pressure.