Proximate Two-Dimensional Electron and Hole Gases in Ambipolar Cuprates

非技术描述：支配原子如何相互作用的定律与我们在日常生活中所习惯的有很大的不同，例如棒球如何在空中飞行或海浪如何移动和相互作用。对于原子，我们的粒子和波的概念融合在一起，量子力学被用来描述它们的相互作用。虽然通常被归入原子尺度，但只有使用量子力学才能解释的行为可以从微观世界超越到宏观世界，并产生一些壮观的效果。例子包括超导性、超流性和相干物质波。这项工作的长期目标是实现相干波的运动对相反的电荷在一个温度下，在固体中，他们可能是有实际意义的。相反电荷对的相干波在其中移动的物质可以为社会提供对下一代电子产品有用的行为。为此，PI将创建包含铜和氧原子的目标结构，并精确控制它们的排列和原子之间的间距。这项研究的更广泛的影响包括培训本科生和研究生使用最先进的技术之一，已知的创造新材料与原子的控制，他们是如何组装。技术专长：该项目的技术目标是生长新的氧化铜基超导体与可调孔或电子移动的载流子浓度。实现可以以可以突然从空穴掺杂切换到电子掺杂的方式掺杂空穴或电子的超导体是合成近二维电子液体和二维空穴液体的道路上的重要一步。这种方法的一个关键优点是所产生的激子系统处于其基态;它不依赖于光激发来产生它，不经历复合，并且因此原则上可以获得高得多的激子载流子浓度，这是一种完全未知的物质状态，其中不寻常的行为（例如，玻色凝聚）。虽然已知氧化物体系可以支持二维电子液体或二维空穴液体，但只有少数氧化物可以以双极方式高度掺杂相同的母相。其中一个突出的是SrCuO 2，所谓的“无限层”铜酸盐，这是所有高转变温度（高Tc）铜酸盐超导体的母体结构。这项研究的更广泛的影响包括训练学生使用最复杂的合成技术之一，分子束外延，以创造具有原子级控制组成原子的氧化物材料而闻名。

NON-TECHNICAL DESCRIPTION: The laws that govern how atoms interact differ significantly from what we are used to in everyday life such as how baseballs fly through the air or ocean waves move and interact with each other. For atoms, our notions of particles and waves merge together and quantum mechanics are used to describe their interactions. Although commonly relegated to atomic scales, behavior that is only explainable with the use of quantum mechanics can transcend from the microscopic to the macroscopic world and produce some spectacular effects. Examples include superconductivity, superfluidity, and coherent matter waves. The long-term goal of this work is to achieve coherent waves of moving pairs of opposite charges in a solid at a temperature where they could be of practical importance. Matter within which coherent waves of opposite charge pairs move could provide society with behaviors useful for the next generation of electronics. Toward this end, the PI will create targeted structures containing copper and oxygen atom-by-atom with precise control of their arrangement and the spacing between the atoms. The broader impact of this research includes the training of undergraduate and graduate students to use one of the most sophisticated techniques known for creating new materials with atom-by-atom control of how they are assembled.TECHNICAL DETAILS: The technical objective of this project is to grow new copper-oxide-based superconductors with tunable hole or electron mobile carrier concentrations. Achieving a superconductor that can be doped with holes or electrons in a way that can switch abruptly from hole to electron doping is an important step on the path to synthesizing proximal two-dimensional electron liquids and two-dimensional hole liquids. A key advantage of this approach is that the resulting excitonic system created is in its ground state; it does not rely on optical excitation for its creation, is not subject to recombination, and can thus, in principle, access much higher exciton carrier concentrations, a completely uncharted state of matter where unusual behavior (e.g., Bose condensation) is expected. Although oxide systems are known that can support either two-dimensional electron liquids or two-dimensional hole liquids, there are only a few oxides in which the same parent phase can be highly doped in an ambipolar manner. A standout among these is SrCuO2, the so-called "infinite-layer" cuprate, which is the parent structure of all high transition temperature (high Tc) cuprate superconductors. The broader impact of this research includes the training of students to use one of the most sophisticated synthesis techniques, molecular-beam epitaxy known for creating oxide materials with atomic-level control of the constituent atoms.