{"title":"钯表面的镍薄膜及氧气吸附的影响:结构、电子特性和磁各向异性的 Ab-initio 研究","authors":"","doi":"10.1016/j.susc.2024.122570","DOIUrl":null,"url":null,"abstract":"<div><p>We report first-principles electronic structure calculations of the structural, electronic, and magnetic properties of model epitaxial layers consisting of nickel (Ni) atomic layers deposited on palladium (Pd) substrate, <em>i.e.</em>, Ni(001)<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<span><math><msub><mrow><mrow><mo>(</mo><mn>001</mn><mo>)</mo></mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> where <span><math><mrow><mi>m</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>6</mn></mrow></math></span> and <span><math><mrow><mi>n</mi><mo>=</mo><mn>3</mn><mo>,</mo><mn>10</mn><mo>,</mo></mrow></math></span> are layer thicknesses. We also investigate the effect of oxygen adsorption on the calculated properties. We found variation in magnetization of between <span><math><mrow><mo>≈</mo><mn>0</mn><mo>.</mo><mn>6</mn><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></mrow></math></span> to 1.00 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> across the nickel layers. Also, finite magnetic moments albeit of small values of between 0.2 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> and 0.3 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> is found on the Pd at the interface. This magnetic moment on an otherwise non-magnetic Pd atoms has been adduced to interfacial strain due to lattice mismatch between the Ni and Pd layers at the Ni<span><math><mo>|</mo></math></span>Pd interface. The effect of adsorbed oxygen on the Ni<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<span><math><msub><mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> is that it increases the magnetic moment on the nickel layers. Also, regarding the magnitude of magnetic anisotropy energy (MAE), we found a high perpendicular values of 1.63 meV and 1.37 meV per unit cell respectively for Ni<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<sub>10</sub> (<span><math><mrow><mi>m</mi><mo>=</mo><mn>2</mn><mo>,</mo><mn>6</mn></mrow></math></span>) which are relatively higher than those reported for other transition metal epitaxial layers. However, the presence of oxygen atom on the Ni<span><math><mo>∣</mo></math></span>Pd changes the direction and magnitude of MAE. Indeed, O adsorption favours or enhances in-plane magnetization direction depending on the thickness of the Ni layers for a fixed Pd thickness. Plots of local density of states (LDOS) which include the effect of spin–orbit coupling (SOC), show that in the case of Ni<span><math><mo>∣</mo></math></span>Pd having perpendicular MAE, there appears a new SOC-induced electronic states below and above the Fermi level. These states appears to stabilize this type of magnetic anisotropy. On the other hand, in-plane MAE is characterized by SOC-induced localized states below the Fermi level (E<span><math><msub><mrow></mrow><mrow><mi>F</mi></mrow></msub></math></span>) as well as the lowering of the DOS at the E<span><math><msub><mrow></mrow><mrow><mi>F</mi></mrow></msub></math></span>. Our work explores the physical, magnetic and electronic properties that may be useful in designing Ni<span><math><mo>∣</mo></math></span>Pd-based superlattices for magnetic or spintronic applications.</p></div>","PeriodicalId":22100,"journal":{"name":"Surface Science","volume":null,"pages":null},"PeriodicalIF":2.1000,"publicationDate":"2024-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Ni thin-films on Pd surfaces and effects of oxygen adsorption: Ab-initio study of structures, electronic properties, magnetic anisotropy\",\"authors\":\"\",\"doi\":\"10.1016/j.susc.2024.122570\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>We report first-principles electronic structure calculations of the structural, electronic, and magnetic properties of model epitaxial layers consisting of nickel (Ni) atomic layers deposited on palladium (Pd) substrate, <em>i.e.</em>, Ni(001)<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<span><math><msub><mrow><mrow><mo>(</mo><mn>001</mn><mo>)</mo></mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> where <span><math><mrow><mi>m</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>6</mn></mrow></math></span> and <span><math><mrow><mi>n</mi><mo>=</mo><mn>3</mn><mo>,</mo><mn>10</mn><mo>,</mo></mrow></math></span> are layer thicknesses. We also investigate the effect of oxygen adsorption on the calculated properties. We found variation in magnetization of between <span><math><mrow><mo>≈</mo><mn>0</mn><mo>.</mo><mn>6</mn><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></mrow></math></span> to 1.00 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> across the nickel layers. Also, finite magnetic moments albeit of small values of between 0.2 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> and 0.3 <span><math><msub><mrow><mi>μ</mi></mrow><mrow><mi>B</mi></mrow></msub></math></span> is found on the Pd at the interface. This magnetic moment on an otherwise non-magnetic Pd atoms has been adduced to interfacial strain due to lattice mismatch between the Ni and Pd layers at the Ni<span><math><mo>|</mo></math></span>Pd interface. The effect of adsorbed oxygen on the Ni<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<span><math><msub><mrow></mrow><mrow><mi>n</mi></mrow></msub></math></span> is that it increases the magnetic moment on the nickel layers. Also, regarding the magnitude of magnetic anisotropy energy (MAE), we found a high perpendicular values of 1.63 meV and 1.37 meV per unit cell respectively for Ni<span><math><msub><mrow></mrow><mrow><mi>m</mi></mrow></msub></math></span> <span><math><mo>∣</mo></math></span>Pd<sub>10</sub> (<span><math><mrow><mi>m</mi><mo>=</mo><mn>2</mn><mo>,</mo><mn>6</mn></mrow></math></span>) which are relatively higher than those reported for other transition metal epitaxial layers. However, the presence of oxygen atom on the Ni<span><math><mo>∣</mo></math></span>Pd changes the direction and magnitude of MAE. Indeed, O adsorption favours or enhances in-plane magnetization direction depending on the thickness of the Ni layers for a fixed Pd thickness. Plots of local density of states (LDOS) which include the effect of spin–orbit coupling (SOC), show that in the case of Ni<span><math><mo>∣</mo></math></span>Pd having perpendicular MAE, there appears a new SOC-induced electronic states below and above the Fermi level. These states appears to stabilize this type of magnetic anisotropy. On the other hand, in-plane MAE is characterized by SOC-induced localized states below the Fermi level (E<span><math><msub><mrow></mrow><mrow><mi>F</mi></mrow></msub></math></span>) as well as the lowering of the DOS at the E<span><math><msub><mrow></mrow><mrow><mi>F</mi></mrow></msub></math></span>. Our work explores the physical, magnetic and electronic properties that may be useful in designing Ni<span><math><mo>∣</mo></math></span>Pd-based superlattices for magnetic or spintronic applications.</p></div>\",\"PeriodicalId\":22100,\"journal\":{\"name\":\"Surface Science\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":2.1000,\"publicationDate\":\"2024-08-17\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Surface Science\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0039602824001213\",\"RegionNum\":4,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Surface Science","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0039602824001213","RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
引用次数: 0
摘要
我们报告了由沉积在钯(Pd)基底上的镍(Ni)原子层(即 Ni(001)m∣Pd(001)n 其中 m=1,2,6 和 n=3,10 为层厚度)组成的模型外延层的结构、电子和磁性能的第一原理电子结构计算结果。我们还研究了氧吸附对计算特性的影响。我们发现镍层之间的磁化率变化在 ≈0.6μB 到 1.00μB 之间。此外,在界面处的钯上也发现了有限的磁矩,尽管数值很小,介于 0.2 μB 和 0.3 μB 之间。镍钯界面上的镍层和钯层之间的晶格不匹配导致界面应变,从而在原本无磁性的钯原子上产生了这种磁矩。吸附氧对 Nim ∣Pdn 的影响是增加了镍层上的磁矩。此外,关于磁各向异性能(MAE)的大小,我们发现 Nim ∣Pd10 (m=2,6)每单位晶胞的垂直值分别为 1.63 meV 和 1.37 meV,相对高于其他过渡金属外延层的垂直值。然而,Ni∣Pd 上氧原子的存在改变了 MAE 的方向和大小。事实上,在钯层厚度固定的情况下,镍层的厚度不同,氧的吸附对面内磁化方向的影响也不同。包含自旋轨道耦合(SOC)效应的局部态密度(LDOS)图显示,在具有垂直 MAE 的 Ni∣Pd 情况下,费米水平以下和以上出现了新的 SOC 诱导的电子态。这些状态似乎能稳定这种类型的磁各向异性。另一方面,面内 MAE 的特点是费米水平(EF)以下的 SOC 诱导的局部态以及 EF 处 DOS 的降低。我们的工作探索了物理、磁性和电子特性,这些特性可能有助于设计用于磁性或自旋电子应用的镍∣钯基超晶格。
Ni thin-films on Pd surfaces and effects of oxygen adsorption: Ab-initio study of structures, electronic properties, magnetic anisotropy
We report first-principles electronic structure calculations of the structural, electronic, and magnetic properties of model epitaxial layers consisting of nickel (Ni) atomic layers deposited on palladium (Pd) substrate, i.e., Ni(001) Pd where and are layer thicknesses. We also investigate the effect of oxygen adsorption on the calculated properties. We found variation in magnetization of between to 1.00 across the nickel layers. Also, finite magnetic moments albeit of small values of between 0.2 and 0.3 is found on the Pd at the interface. This magnetic moment on an otherwise non-magnetic Pd atoms has been adduced to interfacial strain due to lattice mismatch between the Ni and Pd layers at the NiPd interface. The effect of adsorbed oxygen on the Ni Pd is that it increases the magnetic moment on the nickel layers. Also, regarding the magnitude of magnetic anisotropy energy (MAE), we found a high perpendicular values of 1.63 meV and 1.37 meV per unit cell respectively for Ni Pd10 () which are relatively higher than those reported for other transition metal epitaxial layers. However, the presence of oxygen atom on the NiPd changes the direction and magnitude of MAE. Indeed, O adsorption favours or enhances in-plane magnetization direction depending on the thickness of the Ni layers for a fixed Pd thickness. Plots of local density of states (LDOS) which include the effect of spin–orbit coupling (SOC), show that in the case of NiPd having perpendicular MAE, there appears a new SOC-induced electronic states below and above the Fermi level. These states appears to stabilize this type of magnetic anisotropy. On the other hand, in-plane MAE is characterized by SOC-induced localized states below the Fermi level (E) as well as the lowering of the DOS at the E. Our work explores the physical, magnetic and electronic properties that may be useful in designing NiPd-based superlattices for magnetic or spintronic applications.
期刊介绍:
Surface Science is devoted to elucidating the fundamental aspects of chemistry and physics occurring at a wide range of surfaces and interfaces and to disseminating this knowledge fast. The journal welcomes a broad spectrum of topics, including but not limited to:
• model systems (e.g. in Ultra High Vacuum) under well-controlled reactive conditions
• nanoscale science and engineering, including manipulation of matter at the atomic/molecular scale and assembly phenomena
• reactivity of surfaces as related to various applied areas including heterogeneous catalysis, chemistry at electrified interfaces, and semiconductors functionalization
• phenomena at interfaces relevant to energy storage and conversion, and fuels production and utilization
• surface reactivity for environmental protection and pollution remediation
• interactions at surfaces of soft matter, including polymers and biomaterials.
Both experimental and theoretical work, including modeling, is within the scope of the journal. Work published in Surface Science reaches a wide readership, from chemistry and physics to biology and materials science and engineering, providing an excellent forum for cross-fertilization of ideas and broad dissemination of scientific discoveries.