CoSn是一种泡利顺磁体,具有相对平坦的d-带,中心在费米能量Ef以下约100 meV。用X射线和中子散射、磁化率和磁化强度、交流磁化率、比热和电阻率测量研究了轻掺杂Fe、In或Ni的CoSn单晶。在刚性能带近似下,掺杂几个百分比的Fe或In的空穴应该使平带更靠近Ef,而掺杂Ni的电子应该使平带更远离Ef。我们提供的证据表明,这种情况确实发生。Fe和In掺杂驱动CoSn朝向磁性,而Ni掺杂抑制CoSn已经很弱的磁性响应。对于Fe与In掺杂,所得到的基态是不同的。对于Fe掺杂的晶体Co 1-xFexSn(0.02 < x < 0.27),磁性和比热数据与自旋玻璃的形成一致,玻璃化转变温度Tg范围为1 K(x=0.02)至10 K(x= 0.27)。粉末和单晶中子衍射发现没有证据的长程磁低于Tg与x = 0.17。对于In掺杂的晶体CoSn 1-yIny,磁化率和索末菲系数γ相对于纯CoSn显著增加,但对于0.05 < y < 0.2没有明显的磁转变指示。掺杂有Ni(Co0.93Ni0.07Sn)的CoSn晶体具有比纯CoSn显著更小的磁化率和γ,与远离Ef的平坦带一致。
英文摘要:
CoSn is a Pauli paramagnet with relatively flat d-bands centered about 100 meV below the Fermi energy Ef. Single crystals of CoSn lightly doped with Fe, In, or Ni are investigated using x-ray and neutron scattering, magnetic susceptibility and magnetization, ac susceptibility, specific heat and resistivity measurements. Within the rigid band approximation, hole doping with a few percent of Fe or In should move the flat bands closer to Ef, whereas electron doping with Ni should move the flat bands further away from Ef. We provide evidence that this indeed occurs. Fe and In doping drive CoSn toward magnetism, while Ni doping suppresses CoSn's already weak magnetic response. The resulting ground state is different for Fe versus In doping. For Fe-doped crystals, Co1-xFexSn, with 0.02 < x < 0.27, the magnetic and specific heat data are consistent with the formation of a spin glass, with a glass transition temperature, Tg, ranging from 1 K for x=0.02 to 10 K for x= 0.27. Powder and single crystal neutron diffraction found no evidence of long-range magnetic order below Tg with x = 0.17. For In-doped crystals, CoSn1-yIny, both the magnetic susceptibility and the Sommerfeld coefficient, gamma, increase substantially relative to pure CoSn, but with no clear indication of a magnetic transition for 0.05 < y < 0.2. CoSn crystals doped with Ni (Co0.93Ni0.07Sn) have a significantly smaller magnetic susceptibility and gamma than pure CoSn, consistent with the flat bands further from Ef.
Exploring the apparent violation of the Mott relation in a noncentrosymmetric kagome ferromagnet
Virginia Tech(弗吉尼亚理工大学);Virginia Tech National Security Institute(弗吉尼亚国家安全研究所);Virginia Tech Center for Quantum Information Science and Engineering(弗吉尼亚量子信息科学与工程中心);University of Virginia(弗吉尼亚大学);Los Alamos National Laboratory(洛斯阿拉莫斯国家实验室);University of California, Davis(加州大学戴维斯分校)
Putative helimagnetic phase in the kagome metal Co_3Sn_2-xIn_xS_2
对强电子相关性产生的拓扑电子相的探索是凝聚态物理的前沿领域。目前作为此类研究平台出现的一类系统是基于过渡金属的所谓戈薇磁体。利用μ子自旋-旋转,我们探索了可果美磁体Co $_{3}$ Sn $_{2-x}$ In $_{x}$ S $_{2}$中的磁关联作为In掺杂的函数,为有趣的无公度螺旋磁(HM)态提供了推定的证据。我们的研究结果表明,而未掺杂的样品表现出的面外铁磁(FM)的基态,在5 ${\%}$的In掺杂的系统进入一个状态,其中FM和面内反铁磁(AFM)相共存。在更高的掺杂下,HM状态出现并且在仅为$x_{\rm cr,1}$ ${\simeq}$ 0.3的临界掺杂水平下成为主导。这表明从FM通过混合态到$x_{\rm cr,1}$的螺旋相的零温度一阶量子相变。此外,在$x_{\rm cr,2}$ ${\simeq}$ 1处,观察到从螺旋相到顺磁相的零温度二级相变,证明了拓扑磁体Co $_{3}$ Sn $_{2-x}$ In $_{x}$ S $_{2}$的相图中的HM量子临界点(QCP)。所观察到的磁性戈薇晶格中的相互作用的多样性驱动该系统的拓扑霍尔响应的非单调变化。
Magnetic fluctuations near the Van Hove singularity in the kagome-lattice Hubbard model at finite doping
Key Laboratory for Microstructural Material Physics of Hebei Province, School of Science, Yanshan University(燕山大学理学院河北省微观结构材料物理重点实验室);School of Physics and Astronomy, and Key Laboratory of Multiscale Spin Physics (Ministry of Education), Beijing Normal University(北京师范大学物理学系与教育部多尺度自旋物理重点实验室)
Synergistic doping and stabilization of magnetically tunable LnTi$_3$(Sb,Sn)$_4$ (Ln:Ce--Gd) kagome metals
Oak Ridge National Laboratory(橡树岭国家实验室);Norfolk State University(诺福克州立大学);University of Central Florida(中佛罗里达大学);Gdansk University of Technology(格但斯克理工大学)
Emergent Fermi-liquid-like phase by melting a holon Wigner crystal in a doped Mott insulator on the kagome lattice
Beihang University(北京航空航天大学);Great Bay University(大湾区大学);Great Bay Institute for Advanced Study(大湾区高等研究院);California State University Northridge(北岭加州州立大学)
FeGe as a building block for the kagome 1:1, 1:6:6, and 1:3:5 families: hidden d-orbital decoupling of flat band sectors, effective models and interaction Hamiltonians
Observation of ubiquitous charge correlations and hidden quantum critical point in hole-doped kagome superconductors
Brown University(布朗大学);Università di Parma(帕尔马大学);Brown Center for Theoretical Physics and Innovation, BCTPI, Brown University(布朗大学理论物理与创新中心);Università di Bologna(博洛尼亚大学);Università di Modena e Reggio Emilia(摩德纳和雷焦艾米利亚大学);University of California Santa Barbara(加州大学圣塔芭芭拉分校);Université Grenoble Alpes(格勒诺布尔阿尔卑斯大学);Laboratoire National des Champs Magnétiques Intenses(强磁场国家实验室);CNRS(法国国家科学研究中心);Université de Toulouse(图卢兹大学);INSA Toulouse(图卢兹国立应用科学学院);European Magnetic Field Laboratory(欧洲强磁场实验室)
Complex magneto-elastic properties in the frustrated kagome-staircase compounds (Co$_{1-x}$Ni$_x$)$_3$V$_2$O$_8$
本文介绍了对Kagome阶梯化合物(Co $_{1-x}$ Ni $_x$)$_3$ V $_2$ O $_8$单晶的高分辨热容和热膨胀实验。母体化合物Co $_3$ V $_2$ O $_8$和Ni $_3$ V $_2$ O $_8$经历了一系列复杂的一级和二级磁相变。低温($T<40$ K)磁熵随着掺杂含量$x$单调地从Ni $_3$ V $_2$ O $_8$中的全S=1 Ni $^{2+}$磁熵演变到Co $_3$ V $_2$ O $_8$中的S=3/2 Co $^{2+}$磁熵的一半。热膨胀系数$α_i$($i = a$、$b$和$c$)显示出所有(Co $_{1-x}$ Ni $_x$)$_3$ V $_2$ O $_8$化合物的强各向异性。低温磁畸变表明Co掺杂(Ni掺杂)具有与沿$a$或$b$($c$)施加单轴压力类似的效果。线性Grüneisen参数$Γ_i$提取的三个主轴$i$和表现出复杂的行为与温度和掺杂。对于每个轴,$Γ_i$和$α_i$在临界浓度$x_c\simeq0.25$下表现出符号变化(在低温下),在该临界浓度下,无公度磁传播矢量发生变化。除了我们的研究,了解多个和复杂的参数(磁挫折,磁各向异性,S=1和S=3/2离子的混合物等)。现在必须使光丰富的磁弹性性能(Co $_{1-x}$ Ni $_x$)$_3$ V $_2$ O $_8$。
Correlated topological band structures of the kagome altermagnets Mn$_3X$ ($X=$ Sn, Ge, Ga)
Beijing National Laboratory for Condensed Matter Physics and Institute of Physics, Chinese Academy of Sciences(中国科学院物理研究所);School of Physical Sciences, University of Chinese Academy of Sciences(中国科学院大学物理科学学院);Institute of Quantum Materials and Physics, Henan Academy of Sciences(河南省科学院量子材料物理研究所);Institute for Applied Physics, University of Science and Technology Beijing(北京科技大学应用物理学院);Songshan Lake Materials Laboratory(松山湖材料实验室)
Evolution of the Chern Gap in Chern Magnet HoMn$_6$Sn$_{6-x}$Ge$_x$
陈氏能隙是一种可以容纳非阿贝尔粒子的独特拓扑特征。Kagome晶格形成没有间隙的Chern绝缘体。在包含磁性后,Kagome系统在晶格中的K点处具有Chern间隙。在这项工作中,Ge掺杂的HoMn $_6$锡$_{6}$的影响进行了研究。可以看出,随着掺杂的增加,在HoMn $_6$ Sn $_{6-x}$ Ge $_x$中形成多堆叠Chern间隙。此外,HoMn $_6$ Ge $_{6}$中的Chern能隙比HoMn $_6$ Sn $_{6}$中的Chern能隙更显著且能量更大。
Electronic and structural properties of Rh- and Pd-based kagome layered shandites from first principles
Niels Bohr Institute, University of Copenhagen(哥本哈根大学尼尔斯·玻尔研究所);Department of Chemical Engineering and Materials Science, University of Minnesota(明尼苏达大学化学工程与材料科学系)