Novel quantum matter in correlated oxides

电子学是从金属开始的。电线是铜制的，触点是镀金的，电流的开关是用热电子管完成的，这是根据当时唯一已知的电子物理原理——真空中单个电荷的控制规律而建立的。以金属为基础的电子技术是热的、笨重的、容易失败的，但它改变了世界，给我们带来了电报、电话、无线电、雷达、电视，在它的黄昏时期，还发明了第一台电子计算机。当材料科学家把一种非金属的东西——半导体硅——通过掺杂杂质，以一种可控的方式把它变成金属时，重大的突破就出现了。这场悄无声息的革命为我们现在所知的电子技术铺平了道路——凉爽、轻便、非常坚固。但它始于基础科学——探索移动电子在晶体中的行为。事实上，第一个晶体管是由贝尔实验室的科学家制造的，不是作为一个有用的设备，而是作为他们的电子能带理论概念的证明。半导体电子学现在是一项成熟的技术。经过几十年制造技术的改进，在价格和性能上都取得了显著的进步。然而，所有的改进都有其局限性，人们普遍认为，半导体电子学的最终极限将在未来十年内达到。然后，在缺乏替代方法的情况下，电子技术将停滞不前。幸运的是，在第一个晶体管问世后的50年里，材料科学并没有停滞不前，尽管基础研究的重点已经从电子的独立行为转移到了电子的合作行为上。范式的转变是从金属到它们的氧化物——构成地壳大部分的矿物的化学表亲。目前所研究的数十万种过渡金属氧化物表现出比元素周期表中发现的几十种金属和半导体元素更丰富的行为范围。它们通常是磁性的，有时是超导的，它们的材料可以随意改变，通过调整它们所包含的移动电子的动能和势能的平衡。这种灵活性背后的关键原理是强大的电子相关性，就像晶体管诞生时一样，材料科学家、物理学家和技术专家的利益是一致的。的确，如果科学的前沿是由我们没有预料到的事情来定义的，那么强关联系统仍然是人类已知的最广泛和最狂野的前沿之一。这项提议联合了日本两个最重要的材料小组，以及来自英国的世界领先的相关电子态专家，目的是探索电子氧化物材料的基础物理学。它建立在东京大学和布里斯托尔大学以及京都大学和圣安德鲁斯大学之间非常成功的现有合作基础上。

Electronics started with metals \lq as given'. Wires were made from copper, contacts were plated with gold and the switching of electronic currents was accomplished using thermionic valves, built around the only electronic physics known at the time - the rules governing a single electric charge in a vacuum. Metal-based electronic technology was hot, heavy and prone to failure, but it changed the world, giving us telegraphs, telephones, radio, radar, television and - in its twilight - the very first electronic computers. The great breakthrough came when material scientists took something which was not a metal - the semiconductor silicon - and to turned it into a metal in a controlled way, by doping it impurities.This quiet revolution paved the way for electronic technology as we now know it - cool, light and remarkably robust. But it began as fundamental science - the quest to understand how mobile electrons behave in a crystal. Indeed the very first transistor was built by scientists in Bell Labs, not as a useful device, but as a proof of concept for their theory of the electronic band. Semiconductor electronics is now a mature technology. Decades of refinement of manufacturing technique have brought remarkable gains in price and performance. All refinement has its limits however, and it is widely believed that the final limits of semiconductor based electronics will be reached in the next ten years. Then, in the absence of alternative approaches, electronic technology will stagnate. Fortunately materials science has not stood still in the fifty years since the first transistor, though the focus of fundamental research has shifted from the independent, to the cooperative behaviour of electrons. The paradigm shift is one from metals to their oxides - chemical cousins of the minerals which make up most of the earth's crust.The hundreds of thousands of transition metal oxides now studied exhibit a far richer range of behaviors than the scant tens of metallic and semiconducting elements found in the periodic table. Often magnetic, sometimes superconducting, they have materials which can be altered at will, by tailoring the balance of kinetic and potential energy of the mobile electrons they contain. The key principle underlying this flexibility is that of strong electronic correlation and here, as at the birth of the transistor, the interests of materials scientists, physicists and technologists are aligned. Indeed, if the frontiers of science are defined by the things we weren't expecting to happen, strongly correlated systems remain one of the broadest and wildest frontiers known to Man.This proposal unites two of the most important materials groups in Japan, with world-leading experts on the correlated electron state from the UK, with the goal of exploring the fundamental physics of electronic oxide materials. It builds upon extremely successful existing collaborations between the Universities of Tokyo and Bristol and Kyoto and St Andrews.