{"title":"Ambipolarity of hydrogen in matter revealed by muons","authors":"Ryosuke Kadono, Hideo Hosono","doi":"10.1080/00018732.2024.2413342","DOIUrl":null,"url":null,"abstract":"Despite being the simplest element, hydrogen (H) exhibits complex behavior in materials due to its unique ambipolar character. In particular, it is recognized as one of the most important impurities in semiconductor physics, because H is often unintentionally incorporated into materials and significantly influences the electrical properties of the host material. One of the few means that have been applied to obtain experimental information about the local electronic state of diluted H is the use of muon (Mu) as pseudo-H. Here, we present an overview on the “ambipolarity model” that provides a new paradigm for the microscopic understanding of Mu-related defects. Its essence lies in the fact that the information Mu yields is not about the equilibrium double-charge transition level (<span><img alt=\"\" data-formula-source='{\"type\":\"image\",\"src\":\"/cms/asset/4fb9b511-84f4-4430-881c-e82bd3c5949c/tadp_a_2413342_ilm0001.gif\"}' src=\"//:0\"/></span><span><img alt=\"\" data-formula-source='{\"type\":\"mathjax\"}' src=\"//:0\"/><math><msup><mi>E</mi><mrow><mo>+</mo><mrow><mo>/</mo></mrow><mo>−</mo></mrow></msup></math></span>) but about the donor/acceptor levels (<span><img alt=\"\" data-formula-source='{\"type\":\"image\",\"src\":\"/cms/asset/966dd945-1120-4423-b15c-bd6c6842ed2c/tadp_a_2413342_ilm0002.gif\"}' src=\"//:0\"/></span><span><img alt=\"\" data-formula-source='{\"type\":\"mathjax\"}' src=\"//:0\"/><math><msup><mi>E</mi><mrow><mn>0</mn><mrow><mo>/</mo></mrow><mo>−</mo></mrow></msup></math></span> and <span><img alt=\"\" data-formula-source='{\"type\":\"image\",\"src\":\"/cms/asset/6566842e-e530-4827-8e46-e67008aa1fec/tadp_a_2413342_ilm0003.gif\"}' src=\"//:0\"/></span><span><img alt=\"\" data-formula-source='{\"type\":\"mathjax\"}' src=\"//:0\"/><math><msup><mi>E</mi><mrow><mo>+</mo><mrow><mo>/</mo></mrow><mo>−</mo><mn>0</mn></mrow></msup></math></span>) associated with the relaxed-excited states of Mu. Most notably, the model resolves serious discrepancies between the implications from implanted-Mu studies and theoretical predictions on the electronic state of H from <i>ab initio</i> density functional theory calculations in oxide semiconductors that have hindered the coherent integration of both Mu and H knowledge. The model also suggests that hydride state (H<span><img alt=\"\" data-formula-source='{\"type\":\"image\",\"src\":\"/cms/asset/06746f1c-06f4-4df6-ba2f-b1ebaac78308/tadp_a_2413342_ilm0004.gif\"}' src=\"//:0\"/></span><span><img alt=\"\" data-formula-source='{\"type\":\"mathjax\"}' src=\"//:0\"/><math><msup><mrow></mrow><mo>−</mo></msup></math></span>) plays important roles in oxide materials, as found in a variety of recent examples. Based on these successes, the model is currently serving as a reliable guide for the interpretation of various Mu states observed in other insulating materials, for which several recent examples are presented.","PeriodicalId":7373,"journal":{"name":"Advances in Physics","volume":null,"pages":null},"PeriodicalIF":35.0000,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Advances in Physics","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1080/00018732.2024.2413342","RegionNum":1,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"PHYSICS, CONDENSED MATTER","Score":null,"Total":0}
引用次数: 0
Abstract
Despite being the simplest element, hydrogen (H) exhibits complex behavior in materials due to its unique ambipolar character. In particular, it is recognized as one of the most important impurities in semiconductor physics, because H is often unintentionally incorporated into materials and significantly influences the electrical properties of the host material. One of the few means that have been applied to obtain experimental information about the local electronic state of diluted H is the use of muon (Mu) as pseudo-H. Here, we present an overview on the “ambipolarity model” that provides a new paradigm for the microscopic understanding of Mu-related defects. Its essence lies in the fact that the information Mu yields is not about the equilibrium double-charge transition level () but about the donor/acceptor levels ( and ) associated with the relaxed-excited states of Mu. Most notably, the model resolves serious discrepancies between the implications from implanted-Mu studies and theoretical predictions on the electronic state of H from ab initio density functional theory calculations in oxide semiconductors that have hindered the coherent integration of both Mu and H knowledge. The model also suggests that hydride state (H) plays important roles in oxide materials, as found in a variety of recent examples. Based on these successes, the model is currently serving as a reliable guide for the interpretation of various Mu states observed in other insulating materials, for which several recent examples are presented.
尽管氢(H)是最简单的元素,但由于其独特的两极特性,它在材料中表现出复杂的行为。特别是,它被认为是半导体物理学中最重要的杂质之一,因为氢经常被无意地掺入材料中,并显著影响主材料的电学特性。利用μ介子(Mu)作为伪氢气,是获得稀释氢气局部电子态实验信息的少数方法之一。在此,我们概述了 "安培极性模型",它为从微观上理解与μ介子有关的缺陷提供了一种新的范式。其本质在于,Mu 所产生的信息不是关于平衡双电荷转换电平(E+/-),而是关于与 Mu 的弛豫激发态相关的供体/受体电平(E0/- 和 E+/-0)。最值得注意的是,该模型解决了植入式 Mu 研究与氧化物半导体中原子密度泛函理论计算对 H 电子状态的理论预测之间的严重差异,这些差异阻碍了 Mu 和 H 知识的协调整合。该模型还表明,氢化物态(H-)在氧化物材料中发挥着重要作用,这在最近的各种实例中都有发现。基于这些成功经验,该模型目前已成为解释在其他绝缘材料中观察到的各种 Mu 状态的可靠指南,并介绍了最近的几个实例。
期刊介绍:
Advances in Physics publishes authoritative critical reviews by experts on topics of interest and importance to condensed matter physicists. It is intended for motivated readers with a basic knowledge of the journal’s field and aims to draw out the salient points of a reviewed subject from the perspective of the author. The journal''s scope includes condensed matter physics and statistical mechanics: broadly defined to include the overlap with quantum information, cold atoms, soft matter physics and biophysics. Readership: Physicists, materials scientists and physical chemists in universities, industry and research institutes.