Many-body effects in quantized semiconductor electron accumulation layers

虽然大多数材料在其表面不存在电荷载流子，但已经发现了许多半导体，它们可以在表面支持大量电子的积累。这在半导体表面产生了一个势阱，导致导带态量子化为二维子带。我们将采用高分辨率角分辨光电子能谱（ARPES）测量这些量子化状态的技术重要的材料，InAs，InSb，InN，和ZnO，结合互补角集成光电子能谱测量和散装电气和光学研究。虽然通常在单电子图像中处理，但固体是非常复杂的多体系统，其中电子-电子（e-e）和电子-声子（e-ph）相互作用等过程可以导致材料电子结构的显着重整化，这可以证明在确定其基本属性时至关重要。这种效应迄今被忽略在这些量子化的电子积累层的研究。使用ARPES，我们将在这些系统中进行多体过程的详细表征，包括它们对温度，量子阱内的电子密度以及宿主材料的有效质量和德拜温度等因素的依赖性。这项可行性研究不仅将深入了解量子化半导体电子积累层，这对这些技术上重要的材料的应用很重要，而且还将展示它们作为模型系统的用途，用于研究固体中多体相互作用的基本特征。因此，它对理解各种固体的电子性质具有影响，不仅包括半导体，还包括金属、高度相关的电子材料和高Tc超导体。

While most materials have an absence of charge carriers at their surface, a number of semiconductors have been discovered which can support a large build up of electrons at the surface. This creates a potential well at the surface of the semiconductor, causing the conduction band states to become quantized into two-dimensional subbands. We will employ high-resolution angle resolved photoemission spectroscopy (ARPES) measurements of these quantized states in the technologically important materials, InAs, InSb, InN, and ZnO, in conjunction with complementary angle integrated photoemission spectroscopy measurements and bulk electrical and optical studies. While often treated in a one-electron picture, solids are immensely complex many-body systems where processes such as electron-electron (e-e) and electron-phonon (e-ph) interactions can lead to a pronounced renormalization of the material's electronic structure, which can prove essential in determining their fundamental properties. Such effects have hitherto been neglected in the study of these quantized electron accumulation layers. Using ARPES, we will perform a detailed characterisation of the many-body processes in these systems, including their dependence on factors such as temperature, the electron density within the quantum well, and the effective mass and Debye temperature of the host material. This feasibility study will not only develop a thorough understanding of quantized semiconductor electron accumulation layers, important for application of these technologically important materials, but also intends to demonstrate their use as model systems for investigating fundamental features of many-body interactions in solids. Consequently, it has implications for understanding the electronic properties of a wide range of solids, including not only semiconductors but also, for example, metals, highly-correlated electron materials and high-Tc superconductors.