标题： 稀释弱局域金属中接近金属-绝缘体转变的强电子-电子相互作用 显示英文标题

标题： Strong electron-electron interactions in a dilute weakly-localized metal near a metal-to-insulator transition

摘要： 由于通过化学掺杂或电场栅控很容易从绝缘体转变为金属，硅是现代信息技术的核心，并且仍然是量子计算的候选平台。 这种材料的金属-绝缘体转变因此成为凝聚态物理中最被研究的现象之一，每当引入一种新的制造技术时，都会从中获得相当大的收益。 在这里，我们利用了最近在创建类似玻尔原子的掺杂层方面的进展，实现了在半填充情况下二维无序 Hubbard 模型及其金属-绝缘体转变（MIT）作为原子间平均距离的函数。 我们使用气相掺杂前驱分子在硅上进行掺杂，以创建厚度仅为 0.4~nm 且稀释度高达 10$^{13}$~cm$^{-2}$的砷和磷$\delta$-层。 在接近绝缘态时，常规的弱局域化效应在高掺杂浓度下普遍存在，这是由于平面内电子的轨道运动引起的，现在则被电子-电子相互作用贡献所主导，这些贡献遵循顺磁 Zeeman 标度定律。 后者对电导率有负贡献，因此不能用靠近 MIT 的涌现 Kondo 区域来解释。 显示英文摘要

摘要： Because it is easily switched from insulator to metal either via chemical doping or electrical gating, silicon is at the core of modern information technology and remains a candidate platform for quantum computing. The metal-to-insulator transition in this material has therefore been one of the most studied phenomena in condensed matter physics, and has been revisited with considerable profit each time a new fabrication technology has been introduced. Here we take advantage of recent advances in creating ultra-thin layers of Bohr-atom-like dopants to realize the two-dimensional disordered Hubbard model at half-filling and its metal-to-insulator transition (MIT) as a function of mean distance between atoms. We use gas-phase dosing of dopant precursor molecules on silicon to create arsenic and phosphorus $\delta$-layers as thin as 0.4~nm and as dilute as 10$^{13}$~cm$^{-2}$. On approaching the insulating state, the conventional weak localization effects, prevalent at high dopant densities and due to orbital motion of the electrons in the plane, become dominated by electron-electron interaction contributions which obey a paramagnetic Zeeman scaling law. The latter make a negative contribution to the conductance, and thus cannot be interpreted in terms of an emergent Kondo regime near the MIT.