Muyao Wang, Xiaohan Liu, Xiaowei Huang and Liangliang Liu
{"title":"通过金属化σ电子实现层状金属硼化物 Li2BC3 和 LiBC 的表面诱导高温超导性","authors":"Muyao Wang, Xiaohan Liu, Xiaowei Huang and Liangliang Liu","doi":"10.1039/D4NR01482K","DOIUrl":null,"url":null,"abstract":"<p >Metallizing σ electrons provides a promising route to design high-temperature superconducting materials, such as MgB<small><sub>2</sub></small> and high-pressure hydrides. Here, we focus on two MgB<small><sub>2</sub></small>-like layered carborides Li<small><sub>2</sub></small>BC<small><sub>3</sub></small> and LiBC; their bulk does not have superconductivity because the B–C σ states are far away from the Fermi level (<em>E</em><small><sub>F</sub></small>), however, based on first-principles calculations, we found that when their bulk systems are cleaved into surfaces with B–C termination, high <em>T</em><small><sub>c</sub></small> of ∼80 K could be observed in the exposed B–C layer on the surfaces. Detailed analysis reveals that surface symmetry reduction, due to lattice periodic breaking, not only introduces hole self-doping into surface B–C layers and shifts the σ-bonding states towards the <em>E</em><small><sub>F</sub></small> – associated with emergent large electronic occupation, but also makes in-plane stretching modes on the surface layer experience significant softness. The enhanced σ states and softened phonon modes work to produce strong coupling, thus yielding high-<em>T</em><small><sub>c</sub></small> surface superconductivity, which distinctly differs from the superconducting features of the MgB<small><sub>2</sub></small> film, which generates phonon stiffness accompanied by suppressed superconductivity. Our findings undoubtedly provide a novel platform to realize high-<em>T</em><small><sub>c</sub></small> surface superconductivity, and also clearly elucidate the microscopic mechanism of surface-enhanced superconductivity in favor of creating more high-<em>T</em><small><sub>c</sub></small> surface superconductors among MgB<small><sub>2</sub></small>-like layered materials.</p>","PeriodicalId":92,"journal":{"name":"Nanoscale","volume":null,"pages":null},"PeriodicalIF":5.8000,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Surface inducing high-temperature superconductivity in layered metal carborides Li2BC3 and LiBC by metallizing σ electrons†\",\"authors\":\"Muyao Wang, Xiaohan Liu, Xiaowei Huang and Liangliang Liu\",\"doi\":\"10.1039/D4NR01482K\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p >Metallizing σ electrons provides a promising route to design high-temperature superconducting materials, such as MgB<small><sub>2</sub></small> and high-pressure hydrides. Here, we focus on two MgB<small><sub>2</sub></small>-like layered carborides Li<small><sub>2</sub></small>BC<small><sub>3</sub></small> and LiBC; their bulk does not have superconductivity because the B–C σ states are far away from the Fermi level (<em>E</em><small><sub>F</sub></small>), however, based on first-principles calculations, we found that when their bulk systems are cleaved into surfaces with B–C termination, high <em>T</em><small><sub>c</sub></small> of ∼80 K could be observed in the exposed B–C layer on the surfaces. Detailed analysis reveals that surface symmetry reduction, due to lattice periodic breaking, not only introduces hole self-doping into surface B–C layers and shifts the σ-bonding states towards the <em>E</em><small><sub>F</sub></small> – associated with emergent large electronic occupation, but also makes in-plane stretching modes on the surface layer experience significant softness. The enhanced σ states and softened phonon modes work to produce strong coupling, thus yielding high-<em>T</em><small><sub>c</sub></small> surface superconductivity, which distinctly differs from the superconducting features of the MgB<small><sub>2</sub></small> film, which generates phonon stiffness accompanied by suppressed superconductivity. Our findings undoubtedly provide a novel platform to realize high-<em>T</em><small><sub>c</sub></small> surface superconductivity, and also clearly elucidate the microscopic mechanism of surface-enhanced superconductivity in favor of creating more high-<em>T</em><small><sub>c</sub></small> surface superconductors among MgB<small><sub>2</sub></small>-like layered materials.</p>\",\"PeriodicalId\":92,\"journal\":{\"name\":\"Nanoscale\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.8000,\"publicationDate\":\"2024-06-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nanoscale\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://pubs.rsc.org/en/content/articlelanding/2024/nr/d4nr01482k\",\"RegionNum\":3,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CHEMISTRY, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nanoscale","FirstCategoryId":"88","ListUrlMain":"https://pubs.rsc.org/en/content/articlelanding/2024/nr/d4nr01482k","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
Surface inducing high-temperature superconductivity in layered metal carborides Li2BC3 and LiBC by metallizing σ electrons†
Metallizing σ electrons provides a promising route to design high-temperature superconducting materials, such as MgB2 and high-pressure hydrides. Here, we focus on two MgB2-like layered carborides Li2BC3 and LiBC; their bulk does not have superconductivity because the B–C σ states are far away from the Fermi level (EF), however, based on first-principles calculations, we found that when their bulk systems are cleaved into surfaces with B–C termination, high Tc of ∼80 K could be observed in the exposed B–C layer on the surfaces. Detailed analysis reveals that surface symmetry reduction, due to lattice periodic breaking, not only introduces hole self-doping into surface B–C layers and shifts the σ-bonding states towards the EF – associated with emergent large electronic occupation, but also makes in-plane stretching modes on the surface layer experience significant softness. The enhanced σ states and softened phonon modes work to produce strong coupling, thus yielding high-Tc surface superconductivity, which distinctly differs from the superconducting features of the MgB2 film, which generates phonon stiffness accompanied by suppressed superconductivity. Our findings undoubtedly provide a novel platform to realize high-Tc surface superconductivity, and also clearly elucidate the microscopic mechanism of surface-enhanced superconductivity in favor of creating more high-Tc surface superconductors among MgB2-like layered materials.
期刊介绍:
Nanoscale is a high-impact international journal, publishing high-quality research across nanoscience and nanotechnology. Nanoscale publishes a full mix of research articles on experimental and theoretical work, including reviews, communications, and full papers.Highly interdisciplinary, this journal appeals to scientists, researchers and professionals interested in nanoscience and nanotechnology, quantum materials and quantum technology, including the areas of physics, chemistry, biology, medicine, materials, energy/environment, information technology, detection science, healthcare and drug discovery, and electronics.