Materials Today Physics最新文献_第8页

Revisiting thermoelectric transport in 122 Zintl phases: Anharmonic phonon renormalization and phonon localization effects 回顾122个Zintl相的热电输运：非谐波声子重整化和声子局域化效应

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-06 DOI: 10.1016/j.mtphys.2025.101979

Zhenguo Wang , Yinchang Zhao , Jun Ni , Zhenhong Dai

We present a comprehensive study of the thermoelectric properties of hexagonal Zintl-phase compounds XMg₂Y₂ (X=Ca, Sr, Ba; Y=As, Sb, Bi) by combining lattice dynamics and electronic transport calculations. Our results reveal that anharmonic phonon renormalization (APRN) systematically enhances the lattice thermal conductivity through modifications of the phonon velocity operator and temperature-dependent evolution of the scattering phase space. The pronounced double-band-gap feature in the phonon dispersion, arising from the significant mass mismatch between VA-group and alkaline-earth elements, promotes phonon mode localization, thereby intensifying phonon scattering despite a reduction in the weighted phase space. In addition, phonon localization is found to originate from bond anisotropy and the weak local coordination of Ca atoms, while phonon tunneling beyond the Peierls’s framework plays only a minor role in lattice thermal transport. On the electronic side, the intrinsic SOC effect of Bi atoms splits the band-edge degeneracy, suppressing the Seebeck coefficient and moderating

Z T

enhancement. By combining lattice and electronic contributions, we obtain a maximum

Z T

approaching unity in intrinsic CaMg₂Bi₂ at 700 K. Although not yet sufficient for practical devices, these findings establish 122-phase XMg₂Y₂ as a promising intrinsic p-type thermoelectric platform with excellent thermal stability, maintaining structural robustness even up to 1000 K, and underscore the broader importance of mass disparity, bonding anisotropy, and SOC-induced band splitting in guiding the design of next-generation thermoelectric materials

本文通过结合晶格动力学和电子输运计算，对六方zintl相化合物XMg2Y2（X=Ca,Sr,Ba； Y=As,Sb,Bi）的热电性质进行了综合研究。我们的研究结果表明，非谐波声子重整化（APRN）通过改变声子速度算子和散射相空间的温度依赖演化，系统地增强了晶格的导热性。声子色散中明显的双带隙特征是由va族和碱土元素之间的显著质量不匹配引起的，这促进了声子模式的局域化，从而加剧了声子散射，尽管加权相空间减小了。此外，发现声子局域化源于键的各向异性和Ca原子的弱局部配位，而超越Peierls框架的声子隧穿在晶格热输运中只起很小的作用。在电子方面，Bi原子的固有SOC效应分裂了带边简并，抑制了塞贝克系数并减缓了ZT增强。通过结合晶格和电子贡献，我们得到了在700k时CaMg2Bi2的最大ZT接近于单位。虽然还不足以用于实际器件，但这些发现证明了122相XMg2Y2是一种有前途的p型热电平台，具有优异的热稳定性，即使在1000 K下也能保持结构稳健性，并强调了质量差异、键合各向异性和soc诱导的带分裂在指导下一代热电材料设计中的广泛重要性

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引用次数: 0

PbS quantum dots-derived gradient interfaces unify doping and strain for enhanced Bi0.5Sb1.5Te3 thermoelectrics PbS量子点衍生梯度界面统一掺杂和应变增强Bi0.5Sb1.5Te3热电材料

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-06 DOI: 10.1016/j.mtphys.2025.101975

Min Ruan , Minwen Yang , Qing Cao , Wenjie Li , Yanqi Huang , Zehao Lin , Jingyi Lyu , Zeqing Hu , Jing Shuai

Enhancing near-room-temperature p-type (Bi, Sb)₂Te₃ has long been hindered by an intrinsic trade-off in nano structure interfacial engineering: incoherent interfaces strongly scatter phonons but penalize carrier transport, whereas coherent interfaces preserve mobility but provide limited phonon scattering. Here we propose an in-situ multifunctional interfacial strategy enabled by PbS quantum dots (QDs), which self-assembles a chemically graded layer and strong localized strain fields around the QDs during densification. High-resolution electron energy loss spectroscopy (EELS) evidences a continuous compositional gradient that acts as a broad-spectrum phonon scatterer and an intrinsic dopant reservoir. Geometrical phase analysis (GPA) directly reveals intense, localized strain hotspots that lower the formation energy of host-type acceptor defects and modulate the electronic density of states. Experimentally, even 0.1 wt% PbS QDs increase the hole concentration from 1.2 × 10¹⁹ cm⁻³ to 2.4 × 10¹⁹ cm⁻³. Despite moderate decreases in mobility and Seebeck coefficient, a room-temperature power factor of ∼41 μW cm⁻¹ K⁻² is achieved. Subsequent Ga co-doping fine-tunes the carrier density and further suppresses the lattice thermal conductivity, yielding a ZT_max of 1.33 at 350 K (∼20 % higher than the pristine sample) and ZT_ave of 1.12 from 300 to 475 K. Control experiments with elemental Pb, S and micrometer-sized PbS indicate that nanoscale morphology and the resulting in-situ graded interface, rather than chemical composition alone, are essential to the observed synergistic enhancement. This work establishes a generalizable paradigm that intrinsically unifies chemical doping, strain engineering, and multiscale phonon blocking within a single interfacial zone to overcome electron-phonon coupling constraints in near-room-temperature thermoelectric.

增强近室温p型（Bi, Sb）2Te3长期以来一直受到纳米结构界面工程中固有权衡的阻碍：非相干界面强烈散射声子但不利于载流子输运，而相干界面保持迁移性但提供有限的声子散射。本文提出了一种基于PbS量子点（QDs）的原位多功能界面策略，该策略在致密化过程中自组装化学梯度层和QDs周围的强局域应变场。高分辨率电子能量损失谱（EELS）证明了一个连续的成分梯度，它作为一个广谱声子散射体和一个内在的掺杂库。几何相位分析（GPA）直接揭示了强烈的局部应变热点，这些热点降低了宿主型受体缺陷的形成能量并调节了态的电子密度。实验表明，即使0.1 wt% PbS量子点也能使空穴浓度从1.2 × 1019 cm−3增加到2.4 × 1019 cm−3。尽管迁移率和塞贝克系数略有下降，但室温功率因数达到了~ 41 μW cm−1 K−2。随后的Ga共掺杂微调了载流子密度，进一步抑制了晶格热导率，在350 K时产生的ZTmax为1.33（比原始样品高20%），在300至475 K时产生的ZTave为1.12。元素Pb、S和微米级PbS的对照实验表明，纳米尺度的形貌和生成的原位梯度界面，而不仅仅是化学成分，是观察到的协同增强的关键。这项工作建立了一个可推广的范例，该范例内在地统一了化学掺杂，应变工程和单一界面区域内的多尺度声子阻塞，以克服近室温热电中的电子-声子耦合约束。

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引用次数: 0

Self-supported electrodes for efficient water splitting: Integrating wettability with multidimensional engineering 自支撑电极高效水分裂：整合润湿性与多维工程

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-05 DOI: 10.1016/j.mtphys.2025.101977

Leihuan Mu , Qinghua Liu , Jiehui Li , Hui Liu , Pu Feng , Ying Zhang , Jinmei He , Mengnan Qu

With the ongoing global energy transition and the implementation of the “carbon peak–carbon neutrality” strategy, electrocatalytic water splitting has been recognized as a pivotal technology for sustainable hydrogen production owing to its cleanliness and high efficiency. However, conventional powder-based electrodes still suffer from intrinsic drawbacks in electrical conductivity, structural durability, and gas evolution dynamics, making it challenging to achieve high current densities and long-term operational stability. In recent years, self-supported electrodes, benefiting from their integrated current collector–catalyst architecture, have demonstrated remarkable electron/ion transport, mechanical robustness, and highly designable three-dimensional porous structures, thereby emerging as the research frontier in electrolytic water splitting. Notably, precise regulation of electrode surface wettability has been proven to play a decisive role in governing reactant transport, bubble detachment kinetics, and the construction of triple-phase boundaries, thus serving as a key factor to enhance both catalytic activity and durability. This review highlights the synergistic interplay between wettability engineering and multidimensional strategies—including structural engineering, electronic structure modulation, interfacial engineering, and compositional regulation—revealing the intrinsic logic of cross-scale optimization for superior electrode performance. Furthermore, we propose a self-supported electrode design framework centered on the ternary synergy of “structure–wettability–electronics” and provide perspectives on dynamic wettability regulation and advanced in situ characterization techniques for predictive design and mechanistic elucidation. Collectively, this review aims to deliver theoretical insights and technological outlooks toward the rational design and industrial translation of high-performance self-supported electrodes for electrochemical water splitting.

随着全球能源转型和“碳峰碳中和”战略的实施，电催化水分解因其清洁和高效而被公认为可持续制氢的关键技术。然而，传统的粉末电极在导电性、结构耐久性和气体演化动力学方面仍然存在固有的缺点，这使得实现高电流密度和长期运行稳定性具有挑战性。近年来，自支撑电极得益于其集成的集流器-催化剂结构，表现出显著的电子/离子传输、机械稳健性和高度可设计的三维多孔结构，从而成为电解水分解的研究前沿。值得注意的是，电极表面润湿性的精确调节已被证明在控制反应物传输、气泡剥离动力学和三相边界的构建中起着决定性作用，因此是提高催化活性和耐久性的关键因素。这篇综述强调了润湿性工程和多维策略（包括结构工程、电子结构调制、界面工程和成分调节）之间的协同相互作用，揭示了卓越电极性能的跨尺度优化的内在逻辑。此外，我们提出了一个以“结构-润湿性-电子学”三元协同为中心的自支撑电极设计框架，并提供了动态润湿性调节的观点和先进的原位表征技术，用于预测设计和机理阐明。总的来说，本文旨在为电化学水分解的高性能自支撑电极的合理设计和工业转化提供理论见解和技术前景。

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引用次数: 0

Realizing Seebeck-driven transverse thermoelectric generation in bulk composites 在块状复合材料中实现seebeck驱动的横向热电发电

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-05 DOI: 10.1016/j.mtphys.2025.101976

Jangwoo Ha , Min Young Kim , Sang J. Park , Hyungyu Jin

Transverse thermoelectric generation offers a promising alternative to conventional longitudinal thermoelectric modules, potentially mitigating large contact resistances and structural complexities. Among such mechanisms, Seebeck-driven transverse thermoelectric generation (STTG) utilizes Seebeck-induced currents deflected by the Hall effect to produce enhanced transverse thermopower. However, prior demonstrations of STTG have largely relied on bilayer architectures, whose intricate stacking limits fabrication scalability and structural flexibility. Here, we realize STTG in Hall/Seebeck bulk composites fabricated via simple powder metallurgy, eliminating the need for layered construction and enabling isotropic, geometry-independent functionality. Using bismuth and antimony as the Hall and Seebeck materials, respectively, we provide experimental and numerical evidence that STTG operates in Bi/Sb composites, resulting in a 3-fold enhancement in transverse thermopower over the Nernst thermopower of pure Bi and a 7-fold improvement in the transverse thermoelectric figure of merit at 300 K and 0.3 T. These results establish Hall/Seebeck composites as a scalable and fabrication-friendly platform for next-generation transverse thermoelectric energy harvesting.

横向热电发电为传统的纵向热电模块提供了一个有前途的替代方案，潜在地减轻了大的接触电阻和结构复杂性。在这些机制中，塞贝克驱动的横向热电产生（STTG）利用塞贝克感应电流被霍尔效应偏转来产生增强的横向热电功率。然而，先前的STTG演示主要依赖于双层结构，其复杂的堆叠限制了制造的可扩展性和结构灵活性。在这里，我们通过简单的粉末冶金技术在Hall/Seebeck大块复合材料中实现了STTG，消除了分层结构的需要，并实现了各向同性、几何无关的功能。以铋和锑分别作为Hall和Seebeck材料，我们提供了STTG在Bi/Sb复合材料中起作用的实验和数值证据。结果表明，在300 K和0.3 t下，霍尔/塞贝克复合材料的横向热电性能比纯铋的能思特热电性能提高了3倍，横向热电性能提高了7倍。这些结果使霍尔/塞贝克复合材料成为下一代横向热电能量收集的可扩展和易于制造的平台。

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引用次数: 0

Layered-tunnel structure enables high defect tolerance for coexistence of anomalous thermal quenching and mechanoluminescence in Sr2ZnSi2O7:Mn2+ 层状隧道结构使Sr2ZnSi2O7:Mn2+在异常热猝灭和机械发光的同时具有较高的缺陷容忍度

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-05 DOI: 10.1016/j.mtphys.2025.101958

Pan Zhang , Xinyi Jiang , Jingyi Gao , Jiabin Dong , Fan Yang , Tongqing Sun , Li Wu , Yongfa Kong , Yi Zhang , Jingjun Xu

Defect states play an increasingly critical role in regulating the luminescent properties of modern optical materials, as their positions and distributions directly dictate the materials’ luminescent behaviors. A long-standing challenge exists in luminescent materials: elastic-mechanoluminescent (ML) materials rely on shallow trap levels, while photoluminescent materials with high thermal stability require deep trap levels. These conflicting trap level demands make it extremely difficult to simultaneously integrate ML and excellent thermal stability in a single material. Herein, we demonstrate a solution through a layered-tunnel silicate, Sr₂ZnSi₂O₇ (SZS), whose wide bandgap and unique structure offer exceptional defect tolerance. When doped with Mn²⁺, Sr₂ZnSi₂O₇:Mn²⁺ (SZSM) successfully integrates both ML and anomalous thermal quenching properties. The defect-tolerant host allows for the formation of abundant intrinsic oxygen defects at high temperatures, which drive the self-reduction of Mn⁴⁺ to Mn²⁺ and introduce a wide range of defect states within the wide bandgap. The discrete shallow trap levels enable efficient ML under external forces, while the high-concentration, quasi-continuous deep trap bands contribute to anomalous thermal quenching at elevated temperatures. This study demonstrates the feasibility of leveraging layered-tunnel structured materials with high defect tolerance to construct multifunctional luminescent materials via rational defect state engineering. It not only provides a direct solution to the conflicting demands of ML and thermal stability but also offers valuable insights for the development of advanced optical materials.

缺陷态在现代光学材料的发光性能中起着越来越重要的调节作用，它们的位置和分布直接决定了材料的发光行为。在发光材料中存在一个长期存在的挑战：弹性-机械发光（ML）材料依赖于浅阱水平，而具有高热稳定性的光致发光材料需要深阱水平。这些相互冲突的陷阱水平要求使得在单一材料中同时集成ML和优异的热稳定性非常困难。在这里，我们展示了一种通过层状隧道硅酸盐Sr2ZnSi2O7 （SZS）的解决方案，其宽带隙和独特的结构提供了出色的缺陷容忍度。当掺杂Mn2+时，Sr2ZnSi2O7:Mn2+ (SZSM)成功地集成了ML和异常热淬火性能。耐缺陷主体允许在高温下形成丰富的内禀氧缺陷，驱动Mn4+自还原为Mn2+，并在宽带隙内引入广泛的缺陷状态。在外力作用下，离散的浅层陷阱能级能够实现高效的ML，而高浓度、准连续的深层陷阱能带则会导致高温下的异常热猝灭。本研究论证了通过合理的缺陷状态工程，利用高缺陷容限的层状隧道结构材料构建多功能发光材料的可行性。它不仅为ML和热稳定性的冲突需求提供了直接解决方案，而且为先进光学材料的开发提供了宝贵的见解。

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引用次数: 0

Oxygen impurities in wurtzite-type Al1-xBxN alloys: Degraded ferroelectric performance 纤锌矿型Al1-xBxN合金中的氧杂质：降低铁电性能

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-05 DOI: 10.1016/j.mtphys.2025.101969

Jie Su , Yutian Zhao , Zhengmao Xiao , Zhenhua Lin , Jingjing Chang , Jincheng Zhang , Yue Hao

Although the emerged ferroelectric wurtzite (viz. wz-) Al_1-xB_xN alloy excludes oxygen components, its practical application inevitably faces the influence of oxygen impurities due to the negative oxygen doping formation energy. First-principles calculations reveal that oxygen impurities can result in local strain and a negative elastic constant C₁₄, thereby compromising the structural stability and phase transformation concentration of wz-Al_1-xB_xN alloys. Unlike ferroelectric wz-Al_1-xSc_xN alloys, oxygen impurities in wz-Al_1-xB_xN alloys simultaneously degrade spontaneous polarizations and increase polarization switching barriers, irrespective of the oxygen concentration. Moreover, the enhanced polarization switching fields of wz-Al_1-xB_xN_1-yO_y alloys surpass the breakdown electric fields when y > 2.5 %. On one hand, oxygen impurities distort the β-BeO-like structure of the intermediate nonpolar phase and impede the migration of B cations, thereby modifying the polarization switching mechanism. On the other hand, oxygen impurities introduce the strong Al/B-O ionic bonds and elongates the Al-N bond, particularly along the c-axis direction, which increases the internal parameter u and reduces the band gap. Additionally, the elongated Al-N bond within the basal plane shifts the σ∗ anti-bonding orbitals that composed by Al-(p_x + p_y) and N-s orbitals into the band gap of the wz-Al_1-xB_xN_1-yO_y alloy, generating deep impurity levels that mitigate the increase in the leakage currents. These theoretical findings and insights are pivotal for understanding the role of oxygen impurities on the ferroelectric performances and applications of wz-Al_1-xB_xN alloys.

虽然出现的铁电纤锌矿（即wz-） Al1-xBxN合金不含氧成分，但由于氧掺杂形成能为负，其实际应用不可避免地面临氧杂质的影响。第一性原理计算表明，氧杂质会导致wz-Al1-xBxN合金的局部应变和负弹性常数C14，从而影响合金的结构稳定性和相变浓度。与铁电wz-Al1-xScxN合金不同，与氧浓度无关，wz-Al1-xBxN合金中的氧杂质同时降解自发极化并增加极化开关势垒。当y >； 2.5%时，wz-Al1-xBxN1-yOy合金的极化开关电场增强超过击穿电场。一方面，氧杂质扭曲了中间非极性相的β- beo样结构，阻碍了B阳离子的迁移，从而改变了极化开关机制。另一方面，氧杂质引入了强Al/B-O离子键，拉长了Al- n键，特别是沿c轴方向，增加了内部参数u，减小了带隙。此外，基面上Al- n键的拉长将由Al-(px+py)和N-s轨道组成的σ*反键轨道转移到wz-Al1-xBxN1-yOy合金的带隙中，产生较深的杂质水平，从而减缓了泄漏电流的增加。这些理论发现和见解对于理解氧杂质对wz-Al1-xBxN合金铁电性能和应用的作用至关重要。

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引用次数: 0

Disorder-tuned magnetism and magnetocaloric response in a layered SrGd2Al2O7 single crystal 层状SrGd2Al2O7单晶的无序调谐磁性和磁热响应

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-05 DOI: 10.1016/j.mtphys.2025.101970

Ziyu W. Yang , Guoliang Gong , Feifei Yuan , Shuai Tang , Guangkai Zhang , Xubin Ye , Zhao Pan , Yu-Jia Zeng , Youwen Long

We report the magnetic and magnetocaloric responses of SrGd₂Al₂O₇ single crystals, a Ruddlesden-Popper oxide that exhibits intrinsic A-site cation disorder. Structural analysis reveals significant Sr-Gd intermixing, which suppresses long-range magnetic order down to at least 2 K and preserves the full magnetic entropy reservoir of Gd³⁺. To describe the magnetization behavior, we implement a Gaussian-averaged Brillouin (GAB) framework that accounts for the magnetic bond probability and exchange-strength variance arising from the crystallographic disorder. SrGd₂Al₂O₇ exhibits large magnetocaloric responses, achieving a maximum isothermal magnetic entropy change ΔS_mag = 42.6 J kg⁻¹ K⁻¹ and adiabatic temperature change T_ad = 22.0 K at 7 T, surpassing the benchmark coolant Gd₃Ga₅O₁₂ under comparable conditions. The lattice entropy contribution is exceptionally low below 20 K, further establishing SrGd₂Al₂O₇ as a highly competitive cryogenic refrigerant and highlighting controlled structural disorder as a potent design strategy for high-performance magnetocaloric materials.

我们报道了SrGd2Al2O7单晶的磁性和磁热响应，这是一种具有内在a位阳离子无序性的Ruddlesden-Popper氧化物。结构分析表明，Sr-Gd混合作用显著，抑制了Gd3+的远程磁序，使其保持了完整的磁熵库。为了描述磁化行为，我们实现了一个高斯平均布里渊（GAB）框架，该框架考虑了由晶体学紊乱引起的磁键概率和交换强度方差。SrGd2Al2O7表现出较大的磁热响应，在7 T时实现了最大的等温磁熵变化ΔSmag = 42.6 J kg−1 K−1和绝热温度变化Tad = 22.0 K，超过了基准冷却剂Gd3Ga5O12。晶格熵的贡献在20 K以下非常低，进一步确立了SrGd2Al2O7作为一种极具竞争力的低温制冷剂，并强调了控制结构无序是高性能磁热材料的有效设计策略。

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引用次数: 0

Achieving decoupled thermal and electrical transport in BaLiX (X = P, As, Sb, Bi) Zintl phases compounds via anion engineering 通过阴离子工程实现BaLiX (X = P, As, Sb, Bi) Zintl相化合物的热电耦合输运

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-04 DOI: 10.1016/j.mtphys.2025.101974

Ning Wang , Jincheng Yue , Hui Zhang , Siqi Guo , Shuli Li , Yuanhong Tao , Yanhui Liu , Tian Cui

Developing materials with low thermal conductivity and a high power factor is crucial for the practical applications of thermoelectrics. The ZrBeSi-type structure has attracted significant research interest owing to its unique planar honeycomb lattice, which facilitates excellent electrical and thermal transport properties. In this work, we investigated the thermoelectric properties of ZrBeSi-type Zintl phase compounds BaLiX (X

=

P, As, Sb, Bi) using first-principles calculations based on density functional theory. Our results demonstrate that anion engineering decouples the thermal and electrical transport, leading to enhanced thermoelectric performance. Specifically, BaLiP exhibits the lowest lattice thermal conductivity (

κ_{L}

) of only 0.76 W m⁻¹ K⁻¹, which arises from its large phonon bandwidth that significantly enlarges the scattering phase space leading to stronger scattering effects that ultimately suppress

κ_{L}

. Moreover, the combination of a small direct band gap, multiple degenerate bands, and pronounced anisotropy electronic band structure in BaLiBi enables a high Seebeck coefficient and remarkable electrical conductivity. Consequently, enabled by anion engineering, n-type BaLiP achieves a

Z T

value of 1.01, attributed to its suppressed

κ_{L}

, while n-type BaLiBi reaches a

Z T

of 1.05 due to its outstanding power factor. Our work highlights anion engineering as a viable strategy for decoupling electronic and thermal transport, and elucidates the underlying physical mechanism governing the anomalous mass dependence of lattice thermal conductivity in ZrBeSi-type Zintl compounds.

开发具有低导热系数和高功率因数的材料对于热电的实际应用至关重要。zrbesi型结构由于其独特的平面蜂窝晶格，具有优异的电学和热输运性能而引起了人们的极大兴趣。本文采用基于密度泛函理论的第一性原理计算方法研究了zrbesi型Zintl相化合物BaLiX （X == P, As, Sb, Bi）的热电性质。我们的研究结果表明，阴离子工程解耦了热电传输，从而提高了热电性能。具体来说，BaLiP的晶格热导率（κ l - l）最低，仅为0.76 W m−1 K−1，这是由于它的大声子带宽显著扩大了散射相空间，导致散射效应更强，最终抑制了κ l - κ l。此外，小的直接带隙、多个简并带和明显的各向异性电子带结构使BaLiBi具有高的塞贝克系数和卓越的导电性。因此，通过阴离子工程使能，n型BaLiP的ZTZT值为1.01，这是由于其抑制了κ l - κ l，而n型BaLiP的ZTZT值为1.05，这是由于其出色的功率因数。我们的工作强调了阴离子工程作为解耦电子和热输运的可行策略，并阐明了控制zrbesi型Zintl化合物中晶格热导率异常质量依赖的潜在物理机制。

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引用次数: 0

Mg vacancy and impurity-limited MgO single crystal thermal conductivity 镁空位和杂质限制的MgO单晶导热性

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-04 DOI: 10.1016/j.mtphys.2025.101973

Hao Zhou , Hyun Woo , Jesús Carrete , Zilong Hua , Shantanu Saha , Hyejin Jang , Tianli Feng

Magnesium oxide (MgO) exhibits one of the highest thermal conductivities among oxides and is widely used as a dielectric material and substrate in semiconductor devices, in refractory applications, and as a promising filler in thermal interface materials for electronics. Its high thermal conductivity may be sensitive to impurity and defects, yet this influence is still uncertain. Here, the impact of the common impurities, i.e., Al, Ca, Ti, V, Fe, Si, B, Nb, Zr, Na, and K, as well as Mg and O vacancies on phonon scattering and thermal conductivity of MgO is studied using a fully first-principles T-matrix framework. It is found that B, Nb, and Zr impurities, along with Mg vacancies, lead to exceptionally strong reductions in thermal conductivity. By contrast, O vacancies and other impurities have modest to minimal impacts. Leveraging the T-matrix results, we reassess the perturbative, mass-only formalism whose use is pervasive in the literature and show that neglecting bond disorder does not necessarily lead to underestimation: for all transition-metal impurities studied, bond perturbations partially cancel mass disorder, causing the traditional perturbative model to overestimate scattering. We propose a simple modified perturbative expression that incorporates both mass and bond disorder and closely reproduces the T-matrix trends. Our predicted low-temperature trends by including phonon-impurity and phonon-boundary scattering match reasonably well with experiments. This work provides an in-depth study of impurity- and vacancy-limited thermal conductivity of MgO and suggests that reported “high-purity” MgO values have likely not yet reached the intrinsic upper limit, which may be substantially higher.

氧化镁（MgO）是氧化物中热导率最高的材料之一，被广泛用作半导体器件的介电材料和衬底，在耐火材料应用中，也是一种很有前途的电子热界面材料填料。它的高导热系数可能对杂质和缺陷敏感，但这种影响仍不确定。本文采用完全第一性原理的t矩阵框架，研究了常见杂质Al、Ca、Ti、V、Fe、Si、B、Nb、Zr、Na和K以及Mg和O空位对MgO声子散射和导热性的影响。发现B， Nb和Zr杂质以及Mg空位导致导热系数异常强烈的降低。相比之下，O空位和其他杂质的影响很小。利用t矩阵的结果，我们重新评估了在文献中广泛使用的微扰、仅质量的形式，并表明忽略键无序并不一定会导致低估：对于所有研究的过渡金属杂质，键扰动部分抵消了质量无序，导致传统的微扰模型高估了散射。我们提出了一个简单的修正微扰表达式，它结合了质量和键的无序，并紧密地再现了t矩阵的趋势。利用声子杂质散射和声子边界散射预测的低温趋势与实验结果吻合较好。这项工作对MgO的杂质和空位限制热导率进行了深入的研究，并表明报道的“高纯度”MgO值可能尚未达到固有上限，可能要高得多。

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引用次数: 0

Density functional theory calculations of the bandstructure of cubic boron arsenide 立方砷化硼带结构的密度泛函理论计算

IF 9.7 2区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Materials Today Physics

Pub Date : 2025-12-03 DOI: 10.1016/j.mtphys.2025.101962

A. King , R. Gillen , G. Burwell , B.A. Niyikiza , F.J. Pan , Z.F. Ren , L. Li , K. Kalna

A bandgap of cubic boron arsenide (cBAs) is systematically calculated using various approaches in density functional theory (DFT). We explore how basis set, atomic potential, exchange–correlation functional, and spin–orbit coupling influence the bandgap calculations when using Synopsis QuantumATK (QATK), Quantum ESPRESSO, and VASP codes. Our measurements of indirect and direct bandgaps serve as reference values. We found that using a linear combination of atomic orbitals (LCAO) with an ultra basis set, Pseudo-Dojo norm-conserving pseudopotentials, the HSE06 hybrid exchange–correlation functional, and non-collinear spin–orbit coupling (NSOC) in QATK DFT calculations yields indirect and direct bandgaps of

2.03 eV

and

3.99 eV

, which are very close to our measurements of

2.01 eV

and

4.24 eV

, and recent experimental results of

2.02 eV

and 4.12 eV, respectively. NSOC is critical for accurate bandstructure calculations in relatively wide bandgap materials, and the HSE06 functional and optimised PseudoDojo pseudopotentials play a similar role. Using the more common generalised gradient approximation (GGA) exchange–correlation functional PBE underestimates the indirect and direct bandgaps, with values ranging from

1.13 eV

to

1.36 eV

and from

3.04 eV

to

3.37 eV

, respectively, depending on the type of basis set, potential, and spin–orbit coupling used.

利用密度泛函理论（DFT）中的各种方法系统地计算了立方砷化硼（cBAs）的带隙。我们探讨了基集、原子势、交换相关函数和自旋轨道耦合在使用synopsiquantumatk （QATK）、Quantum ESPRESSO和VASP代码时如何影响带隙计算。我们的间接和直接带隙测量值可作为参考值。我们发现，在QATK DFT计算中使用原子轨道（LCAO）与超基集的线性组合、Pseudo-Dojo范数守恒赝势、HSE06杂化交换相关泛函和非共线自旋轨道耦合（NSOC）可以得到2.03eV2.03eV和3.99eV3.99eV的间接带隙和直接带隙，这与我们的测量值2.01eV2.01eV和4.24eV4.24eV以及最近的实验结果2.02eV2.02eV和4.12 eV非常接近。NSOC对于相对宽带隙材料的精确带结构计算至关重要，HSE06功能和优化的PseudoDojo伪势起着类似的作用。使用更常见的广义梯度近似（GGA）交换相关泛函，PBE低估了间接带隙和直接带隙，根据基集类型、势和自旋轨道耦合的不同，其值分别在1.13eV1.13eV至1.36eV1.36eV和3.04eV3.04eV至3.37eV3.37eV之间。

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引用次数: 0