Electric field-tuned unconventional superconductivity in nanoelectronic devices

量子临界铁电体SrTiO 3和KTaO 3通常是带绝缘体，但可以通过使用离子液体电压门引入电子电荷载体而转化为金属。金属性可以通过简单的几伏电压来打开和关闭，IBM有一个制造大量SrTiO 3基微型晶体管阵列的计划。门控SrTiO_3和KTaO_3在温度低于1 K时变为超导，在温度载流子密度相图中具有超导性的圆顶。最近的一个理论解开了这些材料如何成为超导体的谜团，指出了混合极性模式在创建电子配对状态中的作用。这种洞察力使我们能够预测一系列新材料中的超导性。博士项目建立在midi项目中确定的工作和技能的基础上，以确定可能掺杂电子并调谐到量子临界点的候选反铁电体。将使用脉冲激光沉积制备具有不同化学成分的外延薄膜钙钛矿。纳米电子器件将被制造适合于离子液体门控实验。mK制冷机将用于寻找非常规的超导性，也许具有增强的转变温度，并研究新的金属态和绝缘体-金属转变的电学性质。

The quantum critical ferroelectrics SrTiO3 and KTaO3 are usually band insulators but can be transformed into metals by introducing electron charge carriers using ionic-liquid voltage gates. Metallicity can be switched on and off by the simple application of a few volts and IBM have a programme to fabricate vast arrays of SrTiO3-based micro-transistors. Gated SrTiO3 and KTaO3 become superconducting below 1K with a dome of superconductivity in the temperature carrier-density phase diagram. A recent theory has unlocked the mystery of how such materials become superconductors which points to the role of hybrid polar modes in creating electron pairing states. This insight allows us to anticipate superconductivity in a range of new materials. The PhD project builds on the work and skills ascertained in the midi project to identify candidate anti-ferroelectrics that may be doped with electrons and tuned to quantum critical points. Epitaxial thin-film perovskites with varying chemical compositions will be prepared using pulsed-laser deposition. Nanoelectronic devices will be fabricated appropriate for ionic-liquid gating experiments. mK refrigerators will be used to search for unconventional superconductivity, perhaps with enhanced transition temperatures, and to investigate the electrical properties of the novel metallic state and the insulator-metal transition.