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Pressure-Tuned Intrinsic Anomalous Hall Conductivity in Kagome Magnets RV_(6)Sn_(6)(R=Gd,Tb)
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作者 孔祥明 陶咨成 +8 位作者 张蕊 夏威 陈旭 裴翠颖 应天平 齐彦鹏 郭艳峰 杨小帆 李世燕 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第4期139-151,共13页
Exploration of exotic phenomena in magnetic topological systems is at the frontier of condensed matter physics,holding a significant promise for applications in topological spintronics.However,complex magnetic structu... Exploration of exotic phenomena in magnetic topological systems is at the frontier of condensed matter physics,holding a significant promise for applications in topological spintronics.However,complex magnetic structures carrying nontrivial topological properties hinder its progresses.Here,we investigate the pressure effect on the novel topological kagome magnets GdV_(6)Sn_(6) and TbV_(6)Sn_(6) to dig out the interplay between magnetic Gd/Tb layers and nonmagnetic V-based kagome sublattice.The pressure-tuned magnetic transition temperature Tm in both the compounds exhibit a turning point at the critical pressure P_(c),accompanied with a sign reversal in anomalous Hall effect(AHE).The separation of intrinsic and extrinsic contributions using the Tian-Ye-Jin scaling model suggests that the intrinsic mechanism originating from the electronic Berry curvature holds the priority in the competition with extrinsic mechanism in AHE.The above-mentioned findings can be attributed to the combined effect of pressure-tuned band topology and magnetic interaction in segregated layers.Our results provide a practical route to design and manipulate the intrinsic AHE in magnetic topological materials. 展开更多
关键词 holds FRONTIER hinder
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Decoupling of Rattling Mode and Superconductivity in Filled-Skutterudite Ba_(x)Ir_(4)Sb_(12)
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作者 刘辉 于同旭 +1 位作者 张志华 应天平 《Chinese Physics Letters》 SCIE EI CAS CSCD 2024年第7期132-139,共8页
The rattling mode,an anharmonic vibrational phonon,is widely recognized as a critical factor in the emergence of superconductivity in caged materials.Here,we present a counterexample in a filled-skutterudite supercond... The rattling mode,an anharmonic vibrational phonon,is widely recognized as a critical factor in the emergence of superconductivity in caged materials.Here,we present a counterexample in a filled-skutterudite superconductor Ba_(x)Ir_(4)Sb_(12)(x=0.8,0.9,1.0),synthesized via a high-pressure route.Transport measurements down to liquid 3He temperatures reveal a transition temperature(T_(c))of 1.2 K and an upper critical field(H_(c2))of 1.3 T.Unlike other superconductors with caged structures,the Ba_(x)Ir_(4)Sb_(12)(X=P,As,Sb)family exhibits a monotonic decreasing T_(c) with the enhancement of the rattling mode,as indicated by fitting the Bloch–Grüneisen formula.Theoretical analysis suggests that electron doping from Ba transforms the direct bandgap IrSb3 into a metal,with the Fermi surface dominated by the hybridization of Ir 5d and Sb 5p orbitals.Our findings of decoupled rattling modes and superconductivity distinguish the Ba_(x)Ir_(4)Sb_(12) family from other caged superconductors,warranting further exploration into the underlying mechanism. 展开更多
关键词 mechanism materials SUPERCONDUCTIVITY
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Pressure-Induced Superconductivity in the Charge-Density-Wave Compound LaTe_(2-x)Sb_(x)(x=0 and 0.4)
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作者 陈旭 孙培函 +7 位作者 谢圳楷 孟繁琦 裴翠颖 齐彦鹏 应天平 刘凯 郭建刚 陈小龙 《Chinese Physics Letters》 SCIE EI CAS CSCD 2023年第10期101-107,共7页
Magnetic CeTe_(2)achieving superconductivity under external pressure has received considerable attention.The intermingling of 4f and 5d electrons from Ce raised the speculation of an unconventional pairing mechanism a... Magnetic CeTe_(2)achieving superconductivity under external pressure has received considerable attention.The intermingling of 4f and 5d electrons from Ce raised the speculation of an unconventional pairing mechanism arising from magnetic fluctuations.Here,we address this speculation using a nonmagnetic 4f-electron-free LaTe_(2)as an example.No structural phase transition can be observed up to 35 GPa in the in situ synchrotron diffraction patterns.Subsequent high-pressure electrical measurements show that LaTe_(2)exhibits superconductivity at20 Gpa with its T_(c)(4.5 K)being two times higher than its Ce-counterpart.Detailed theoretical calculations reveal that charge transfer from the 4p orbitals of the planar square Te-Te network to the 5d orbitals of La is responsible for the emergence of superconductivity in LaTe_(2),as confirmed by Hall experiments.Furthermore,we study the modulation of q_(CDW)by Sb substitution and find a record high T_(c)^(onset)~6.5 K in LaTe_(1.6)Sb_(0.4).Our work provides an informative clue to comprehend the role of 5d-4p hybridization in the relationship between charge density wave(CDW)and superconductivity in these RETe_(2)(RE=rare-earth elements)compounds. 展开更多
关键词 SUPERCONDUCTIVITY CHARGE RARE
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Exploring FeSe-based superconductors by liquid ammonia method
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作者 应天平 王刚 +6 位作者 金士锋 申士杰 张韩 周婷婷 赖晓芳 王皖燕 陈小龙 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第8期162-170,共9页
(Received 8 June 2013) Our recent progress on the preparation of a series of new FeSe-based superconductors and the clarification of SC phases in potassium-intercalated iron selenides are reviewed here. By the liqu... (Received 8 June 2013) Our recent progress on the preparation of a series of new FeSe-based superconductors and the clarification of SC phases in potassium-intercalated iron selenides are reviewed here. By the liquid ammonia method, metals Li, Na, Ca, Sr, Ba, Eu, and Yb are intercalated in between FeSe layers and form superconductors with transition temperatures of 30 K^46 K, which cannot be obtained by high-temperature routes. In the potassium-intercalated iron selenides, we demonstrate that at least two SC phases exist, KxFe2Se2(NH3)y (x 0.3 and 0.6), determined mainly by the concentration of potassium. NH3 has little, if any, effect on superconductivity, but plays an important role in stabilizing the structures. All these results provide a new starting point for studying the intrinsic properties of this family of superconductors, especially for their particular electronic structures. 展开更多
关键词 SUPERCONDUCTIVITY iron-based superconductor liquid ammonia critical temperature
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Electrochemical synthesis of alkali-intercalated iron selenide superconductors 被引量:1
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作者 申士杰 应天平 +4 位作者 王刚 金士锋 张韩 林志萍 陈小龙 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第11期488-491,共4页
Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductiv... Electrochemical method has been used to insert K/Na into FeSe lattice to prepare alkali-intercalated iron selenides at room temperature. Magnetization measurement reveals that KxFe2Se2 and NaxFe2Se2 are superconductive at 31 K and 46 K, respectively. This is the first successful report of obtaining metal-intercalated FeSe-based high-temperature superconductors using electrochemical method. It provides an effective route to synthesize metal-intercalated layered compounds for new superconductor exploration. 展开更多
关键词 SUPERCONDUCTIVITY iron-based superconductor electrochemical synthesis INTERCALATION
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Pressure-Induced Topological and Structural Phase Transitions in an Antiferromagnetic Topological Insulator 被引量:1
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作者 裴翠颖 夏云悠悠 +12 位作者 邬家臻 赵毅 高玲玲 应天平 高波 李娜娜 杨文革 张东舟 缑慧阳 陈宇林 细野秀雄 李刚 齐彦鹏 《Chinese Physics Letters》 SCIE CAS CSCD 2020年第6期57-65,共9页
Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We sy... Recently,natural van der Waals heterostructures of(MnBi2 Te4)m(Bi2 Te3)n have been theoretically predicted and experimentally shown to host tunable magnetic properties and topologically nontrivial surface states.We systematically investigate both the structural and electronic responses of MnBi2 Te4 and MnBi4 Te7 to external pressure.In addition to the suppression of antiferromagnetic order,MnBi2 Te4 is found to undergo a metalsemiconductor-metal transition upon compression.The resistivity of MnBi4 Te7 changes dramatically under high pressure and a non-monotonic evolution of p(T)is observed.The nontrivial topology is proved to persist before the structural phase transition observed in the high-pressure regime.We find that the bulk and surface states respond differently to pressure,which is consistent with the non-monotonic change of the resistivity.Interestingly,a pressure-induced amorphous state is observed in MnBi2 Te4,while two high-pressure phase transitions are revealed in MnBi4 Te7.Our combined theoretical and experimental research establishes MnBi2 Te4 and MnBi4 Te7 as highly tunable magnetic topological insulators,in which phase transitions and new ground states emerge upon compression. 展开更多
关键词 nontrivial TOPOLOGICAL RESISTIVITY
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Nodeless superconductivity in a quasi-two-dimensional superconductor AuTe2Se(4/3)
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作者 贾小雨 俞云杰 +5 位作者 陈旭 郭建刚 应天平 何兰坡 陈小龙 李世燕 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第6期87-91,共5页
We performed ultra-low temperature thermal conductivity measurements on the single crystal of a new gold-based quasi-two-dimensional superconductor Au Te2Se(4/3), which has a superconducting transition temperature T... We performed ultra-low temperature thermal conductivity measurements on the single crystal of a new gold-based quasi-two-dimensional superconductor Au Te2Se(4/3), which has a superconducting transition temperature Tc = 2.70 K. A negligible residual linear term κ0/T in zero magnetic field is observed, which suggests fully gapped superconducting state.Furthermore, the field dependence of κ0/T is similar to that of the multi-band s-wave superconductor Ba Fe1.9 Ni0.1 As2 at low field. These results reveal multiple nodeless superconducting gaps in this interesting quasi-two-dimensional superconductor with Berezinsky–Kosterlitz–Thouless topological transition. 展开更多
关键词 SUPERCONDUCTIVITY thermal transport measurement gap structure two-dimensional material
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Two-Dimensional Electron Gas with High Mobility Forming at BaO/SrTiO_(3) Interface
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作者 曹程 陈盛如 +7 位作者 邓俊 李岗 张庆华 谷林 应天平 郭尔佳 郭建刚 陈小龙 《Chinese Physics Letters》 SCIE EI CAS CSCD 2022年第4期41-46,共6页
Two-dimensional electron gas(2DEG)with high electron mobility is highly desired to study the emergent properties and to enhance future device performance.Here we report the formation of 2DEG with high mobility at the ... Two-dimensional electron gas(2DEG)with high electron mobility is highly desired to study the emergent properties and to enhance future device performance.Here we report the formation of 2DEG with high mobility at the interface between rock-salt Ba O and perovskite Sr Ti O_(3).The interface consists of the ionically compensated Ba O_(1-δ) layer and the electronically compensated Ti O_(2) layer,which is demonstrated as a perfect interface without lattice mismatch.The so-formed interface features metallic conductivity with ultralow square resistance of7.3×10^(-4)Ω/□at 2 K and high residual resistance ratios R_(300 K)/R_(2 K) up to 4200.The electron mobility reaches69000 cm^(2)·V^(-1)·s^(-1)at 2 K,leading to Shubnikov–de Haas oscillations of resistance.Density functional theory calculations reveal that the effective charge transfers from Ba O to the Ti 3d_(xy) orbital occur at the interface,leading to the conducting Ti O_(2) layer.Our work unravels that Ba O can adapt itself by removing oxygen to minimize the lattice mismatch and to provide substantial carriers to Sr Ti O_(3),which is the key to forming 2DEGs with high mobility at the interfaces. 展开更多
关键词 INTERFACE ELECTRON RESISTANCE
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Discovery of Two Families of VSb-Based Compounds with V-Kagome Lattice
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作者 杨雨欣 樊文辉 +13 位作者 张庆华 陈昭旭 陈旭 应天平 吴贤新 杨小帆 孟繁琦 李岗 李世燕 谷林 钱天 Andreas P.Schnyder 郭建刚 陈小龙 《Chinese Physics Letters》 SCIE EI CAS CSCD 2021年第12期44-49,共6页
We report the structure and physical properties of two newly discovered compounds AV_(8)Sb_(12)and AV_(6)Sb_(6)(A=Cs,Rb),which have C_(2)(space group:Cmmm)and C_(3)(space group:R3 m)symmetry,respectively.The basic Vka... We report the structure and physical properties of two newly discovered compounds AV_(8)Sb_(12)and AV_(6)Sb_(6)(A=Cs,Rb),which have C_(2)(space group:Cmmm)and C_(3)(space group:R3 m)symmetry,respectively.The basic Vkagome unit appears in both compounds,but stacking differently.AV_(2)Sb_(2) layer is sandwiched between two V_(3)Sb_(5)layers in AV_(8)Sb_(12),altering the V-kagome lattice and lowering the symmetry of kagome layer from hexagonal to orthorhombic.In AV_(6)Sb_(6),the building block is a more complex slab made up of two half-V_(3)Sb_(5)layers that are intercalated by Cs cations along the c-axis.Transport property measurements demonstrate that both compounds are nonmagnetic metals,with carrier concentrations at around 10^(21)cm^(-3).No superconductivity has been observed in CsV_(8)Sb_(12)above 0.3 K under in situ pressure up to 46 GPa.Compared to CSV_(3)Sb_(5),theoretical calculations and angle-resolved photoemission spectroscopy reveal a quasi-two-dimensional electronic structure in CsV_(8)Sb_(12)with C_(2)symmetry and no van Hove singularities near the Fermi level.Our findings will stimulate more research into V-based kagome quantum materials. 展开更多
关键词 SYMMETRY LATTICE HEXAGONAL
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Superconductivity in the Layered Cage Compound Ba_(3)Rh_(4)Ge_(16)
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作者 赵毅 邓俊 +9 位作者 A.Bhattacharyya D.T.Adroja P.K.Biswas 高玲玲 曹渭征 李昌华 裴翠颖 应天平 Hideo Hosono 齐彦鹏 《Chinese Physics Letters》 SCIE EI CAS CSCD 2021年第12期69-75,共7页
We report the synthesis and superconducting properties of a layered cage compound Ba_(3)Rh_(4)Ge_(16).Similar to Ba_(3)Ir_(4)Ge_(16),the compound is composed of 2 D networks of cage units,formed by noncubic Rh-Ge buil... We report the synthesis and superconducting properties of a layered cage compound Ba_(3)Rh_(4)Ge_(16).Similar to Ba_(3)Ir_(4)Ge_(16),the compound is composed of 2 D networks of cage units,formed by noncubic Rh-Ge building blocks,in marked contrast to the reported rattling compounds.The electrical resistivity,magnetization,specific heat capacity,andμSR measurements unveiled moderately coupled s-wave superconductivity with a critical temperature T_(c)=7.0 K,the upper critical field μ_(0)H_(c2)(0)~2.5 T,the electron-phonon coupling strength λ_(e-ph)~0.80,and the Ginzburg-Landau parameterκ~7.89.The mass reduction with the substitution of Ir by Rh is believed to be responsible for the enhancement of T_(c) and coupling between the cage and guest atoms.Our results highlight the importance of atomic weight of framework in cage compounds in controlling the λ_(e-ph) strength and T_(c). 展开更多
关键词 CAGE coupling CRITICAL
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拓扑异质结(PbSe)_(5)(Bi_(2)Se_(3))_(6)高压诱导超导电性研究
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作者 裴翠颖 朱鹏 +16 位作者 李炳谈 赵毅 高玲玲 李昌华 朱世豪 张庆华 应天平 谷林 高波 缑慧阳 姚延荪 孙建 刘寒雨 陈宇林 王秩伟 姚裕贵 齐彦鹏 《Science China Materials》 SCIE EI CAS CSCD 2023年第7期2822-2828,共7页
最近,天然异质结(PbSe)_(5)(Bi_(2)Se_(3))_(6)在理论上预测并实验证实为拓扑绝缘体.本文通过高压原位量子调控在(PbSe)_(5)(Bi_(2)Se_(3))_(6)中成功引入超导电性.当压力增加到10 GPa时,超导电性突然出现,T_(c)约为4.6 K,随后T_(c)急... 最近,天然异质结(PbSe)_(5)(Bi_(2)Se_(3))_(6)在理论上预测并实验证实为拓扑绝缘体.本文通过高压原位量子调控在(PbSe)_(5)(Bi_(2)Se_(3))_(6)中成功引入超导电性.当压力增加到10 GPa时,超导电性突然出现,T_(c)约为4.6 K,随后T_(c)急剧下降.值得注意的是,当进一步施加压力到30 GPa以上时,出现了一种新的超导态,且T_(c)直到本实验最高压力仍未饱和.结合XRD和拉曼光谱,我们认为(PbSe)_(5)(Bi_(2)Se_(3))_(6)中两个超导态的出现与压力诱导的结构相变有关.拓扑异质结压力下出现新的量子态,为进一步研究拓扑和超导的关系提供了一个良好的平台. 展开更多
关键词 high pressure SUPERCONDUCTIVITY HETEROSTRUCTURE topological material
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亚稳态新型铁硒基超导体探索
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作者 刘旭 应天平 《中国科学:物理学、力学、天文学》 CSCD 北大核心 2023年第12期72-85,共14页
插层铁硒基超导体作为铁基超导的重要组成部分,是近年来凝聚态物理领域的研究热点.它们不仅具有高的超导转变温度(T_(c)),而且有着迥异于其他铁基超导体的费米面电子结构,挑战了原有的超导电子配对机理.然而由于电负性平衡的要求,使用... 插层铁硒基超导体作为铁基超导的重要组成部分,是近年来凝聚态物理领域的研究热点.它们不仅具有高的超导转变温度(T_(c)),而且有着迥异于其他铁基超导体的费米面电子结构,挑战了原有的超导电子配对机理.然而由于电负性平衡的要求,使用传统高温固相反应得到的晶体无法避免相分离的发生,其中含有大量Fe空位的非超导相,严重干扰对其本征物性的研究.为获得单相的插层铁硒基超导体,人们提出了液氨法,利用低温获得无Fe空位的插层铁硒基超导亚稳相.随后,溶剂热法和水热法等低温插层方法相继被提出.本文回顾了插层铁硒基超导体的设计理念和发展历程,综述了几种典型低温插层方法及其研究进展,同时提出了未来的研究方向. 展开更多
关键词 铁硒基超导体 亚稳态 低温插层
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表面微结构研究揭示了太空风化作用下嫦娥5号月壤演化的中间阶段 被引量:1
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作者 郭建刚 应天平 +8 位作者 高汉滨 陈旭 宋艳鹏 林挺 张庆华 郑强 李春来 徐义刚 陈小龙 《Science Bulletin》 SCIE EI CAS CSCD 2022年第16期1696-1701,M0004,共7页
月球土壤的组份和微结构会随时间推移发生明显变化,主要原因是其受到微陨石轰击、太阳风或宇宙射线中的带电粒子辐射等太阳风化作用.前期研究表明,太空风化会造成月壤样品表面形成50~200 nm厚的非晶层,层内包裹着大量2~10 nm的金属铁,... 月球土壤的组份和微结构会随时间推移发生明显变化,主要原因是其受到微陨石轰击、太阳风或宇宙射线中的带电粒子辐射等太阳风化作用.前期研究表明,太空风化会造成月壤样品表面形成50~200 nm厚的非晶层,层内包裹着大量2~10 nm的金属铁,但该类表面形貌和组成的起源仍存在争议.嫦娥5号取回的月壤样品属于最年轻的玄武岩,并且取样点的纬度最高,为理解月壤在太空风化作用下的演化规律提供了新的机会和线索.本文系统研究了月壤如铁橄榄石、辉石、长石和玻璃珠的表面形貌及化学组成.与以往报道不同的是,仅在铁橄榄石表面观察到了薄的SiO_(2)非晶层(厚度大约10 nm),发现其中包裹着2~12 nm的方铁矿FeO,并且没有观察到任何纳米金属铁颗粒.同时,在所研究的5种样品表面和内部,没有观察到任何易挥发的外来化学元素(如硫、氯等)和太阳耀斑穿过的痕迹.方铁矿FeO和表面微结构的确立暗示着本研究的月壤可能处于太阳风化所引起的热分解中间阶段. 展开更多
关键词 表面微结构 铁橄榄石 太阳耀斑 月球土壤 带电粒子 玻璃珠 风化作用 中间阶段
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一种新型超导母体:褶皱的蜂窝状空位有序
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作者 齐彦鹏 应天平 +8 位作者 吴贤新 董卓雅 Masato Sasase 张青 刘为燕 Masaki Ichihara 马延航 胡江平 Hideo Hosono 《Science Bulletin》 SCIE EI CSCD 2021年第4期327-331,M0003,共6页
空位在材料体系中无处不在,空位的存在也极大地影响了材料的光学、热学、电学等性质.目前,空位的研究主要集中在弱关联的体系,而在强关联体系中的空位以及空位和其他新奇量子现象的关系则知之甚少.本文在强关联铱化物Ir16Sb18中发现了... 空位在材料体系中无处不在,空位的存在也极大地影响了材料的光学、热学、电学等性质.目前,空位的研究主要集中在弱关联的体系,而在强关联体系中的空位以及空位和其他新奇量子现象的关系则知之甚少.本文在强关联铱化物Ir16Sb18中发现了一种新奇的空位有序:褶皱的蜂窝状空位序.理论计算表明实空间的空位有序来源于倒空间的费米面嵌套,而空位有序的形成破坏了对称性,使得费米面附近的电子局域化.通过在空位中引入Ir或者用Rh来替代Ir,可以有效地破坏空位有序从而引入超导电性.空位有序与超导电性的竞争关系表明:具有褶皱的蜂窝状空位有序的Ir16Sb18是一种新型的超导母体.这种独特的褶皱蜂窝状空位有序,及其实空间-倒空间的关系,表明了"关联空位"的重要性,这为探索更多新奇量子临界现象带来契机. 展开更多
关键词 量子现象 蜂窝状 超导电性 费米面 16S 强关联 弱关联 褶皱
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