Charge order landscape and competition with superconductivity in kagome metals
Mingu Kang, Shiang Fang, Jonggyu Yoo, Brenden R. Ortiz, Yuzki Oey, Jonghyeok Choi, Sae Hee Ryu, Jimin Kim, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Efthimi… 展开作者
Mingu Kang, Shiang Fang, Jonggyu Yoo, Brenden R. Ortiz, Yuzki Oey, Jonghyeok Choi, Sae Hee Ryu, Jimin Kim, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Efthimios Kaxiras, Joseph G. Checkelsky, Stephen D. Wilson, Jae-Hoon Park, Riccardo Comin
In kagome metals AV3Sb5 (A = K, Rb, Cs), three-dimensional charge order (3D-CO) is the primary instability that sets the stage for other collective orders to emerge, including unidirectional stripe order, orbital flux order, electronic nematicity, and superconductivity. Here, we use high-resolution angle-resolved photoemission spectroscopy to determine the microscopic structure of three-dimensional charge order (3D-CO) in AV3Sb5 and its interplay with superconductivity. Our approach is based on identifying an unusual splitting of kagome bands induced by 3D-CO, which provides a sensitive way to refine the spatial charge patterns in neighboring kagome planes. We found a marked dependence of the 3D-CO structure on composition and doping. The observed difference between CsV3Sb5 and the other compounds potentially underpins the double-dome superconductivity in CsV3(Sb,Sn)5 and the suppression of Tc in KV3Sb5 and RbV3Sb5. Our results provide fresh insights into the rich phase diagram of AV3Sb5.
The recently discovered coexistence of superconductivity and charge density wave order in the kagome systems AV3Sb5 (A = K, Rb, Cs) has stimulated enormous interest. According to theory, a vanadium-based kagome system may host a flat band, nontrivial linear dispersive Dirac surface states and electronic correlation. Despite intensive investigations, it remains controversial about the origin of the charge density wave (CDW) order, how does the superconductivity relate to the CDW, and whether the anomalous Hall effect (AHE) arises primarily from the kagome lattice or the CDW order. We report an …
We have employed a magnetic field angle as a tuning parameter in a comprehensive measurement of the specific heat, magnetocaloric effect, and magnetization for the quasi-kagome Kondo lattice CeRhSn, which is considered to exhibit zero-field quantum criticality driven by geometrical frustration. By constructing the field-angle-resolved landscape of the entropy, we unexpectedly revealed that the non-Fermi-liquid nature survives up to a metamagnetic crossover field of roughly 3 T in the very narrow field-orientation range, close to the direction parallel to the quasi-kagome plane. We propose that…
Understanding the competition between superconductivity and other ordered states (such as antiferromagnetic or charge-density-wave (CDW) state) is a central issue in condensed matter physics. The recently discovered layered kagome metal AV3Sb5 (A = K, Rb, and Cs) provides us a new playground to study the interplay of superconductivity and CDW state by involving nontrivial topology of band structures. Here, we conduct high-pressure electrical transport and magnetic susceptibility measurements to study CsV3Sb5 with the highest Tc of 2.7 K in AV3Sb5 family. While the CDW transition is monotonical…
Magnetic competition in topological kagome magnets is studied by incorporating the spin-orbit coupling, the anisotropic Hund coupling and spin exchange into the kagome lattice. Using the Bogoliubov variational principle we find the stable phases at zero and finite temperatures. At zero temperature and in the strong Ising-Hund coupling regime, a magnetic tunability from the out-of-plane ferromagnetism (FM) to the in-plane antiferromagnetism (AFM) is achieved by a universal property of the critical in-plane Hund coupling. At two-thirds filling the phase transition from the out-of-plane FM to the…
The recently discovered layered kagome metals AV$_3$Sb$_5$ (A = K, Rb, and Cs) with vanadium kagome networks provide a novel platform to explore correlated quantum states intertwined with topological band structures. Here we report the prominent effect of hole doping on both superconductivity and charge density wave (CDW) order, achieved by selective oxidation of exfoliated thin flakes. A superconducting dome is revealed as a function of the effective doping content. The superconducting transition temperature ($T_{\mathrm{c}}$) and upper critical field in thin flakes are significantly enhanced…
Magnetic topological phases of quantum matter are an emerging frontier in physics and material science. Along these lines, several kagome magnets have appeared as the most promising platforms. However, the magnetic nature of these materials in the presence of topological state remains an unsolved issue. Here, we explore magnetic correlations in the kagome magnet Co_3Sn_2S_2. Using muon spin-rotation, we present evidence for competing magnetic orders in the kagome lattice of this compound. Our results show that while the sample exhibits an out-of-plane ferromagnetic ground state, an in-plane an…
Spin Liquid Landscapes in the Kagome Lattice: A Variational Monte Carlo Study of the Chiral Heisenberg Model and Experimental Signatures
Korea Advanced Institute of Science and Technology（韩国科学技术院）；University of Notre Dame（圣母大学）；HUN-REN Wigner Research Centre for Physics（匈牙利研究与创新网络维格纳物理研究中心）
We study numerically the spin-1/2 XXZ model in a field on an infinite Kagome lattice. We use different algorithms based on infinite Projected Entangled Pair States (iPEPS) for this, namely: (i) with simplex tensors and 9-site unit cell, and (ii) coarse-graining three spins in the Kagome lattice and mapping it to a square-lattice model with nearest-neighbor interactions, with usual PEPS tensors, 6- and 12-site unit cells. Similarly to our previous calculation at the SU(2)-symmetric point (Heisenberg Hamiltonian), for any anisotropy from the Ising limit to the XY limit, we also observe the emerg…
The recently discovered Kagome family ${\mathrm{AV}}_3{\mathrm{Sb}}_5$ (A = K, Rb, Cs) exhibits rich physical phenomena, including non-trivial topological electronic structure, giant anomalous Hall effect, charge density waves (CDW) and superconductivity. Notably, CDW in ${\mathrm{AV}}_3{\mathrm{Sb}}_5$ is evidenced to intertwine with its superconductivity and topology, but its nature remains elusive. Here, we combine x-ray scattering experiments and density-functional theory calculations to investigate the CDWs in ${\mathrm{CsV}}_3{\mathrm{Sb}}_5$ and demonstrate the coexistence of 2 $\times$…
Electronic nematicity has been commonly observed in juxtaposition with unconventional superconductivity. Understanding the nature of the nematic state, as well as its consequence on the electronic band structure and superconductivity, has become a pivotal focus in condensed matter physics. Here we use spectroscopic imaging-scanning tunneling microscopy to visualize how the interacting quasiparticles organize themselves in the nematic state of kagome superconductor CsV$_{3-x}$Ti$_x$Sb$_5$, in which twofold symmetric (C$_2$) quasiparticle scattering interference of the vanadium kagome bands emer…
Anomalous Low-temperature Magnetotransport in Kagome Metal CsCr$_3$Sb$_5$ under Pressure
The Chinese University of Hong Kong（香港中文大学）；State Key Laboratory of Quantum Information Technologies and Materials, The Chinese University of Hong Kong（香港中文大学量子信息技术与材料国家重点实验室）；Beijing Institute of Technology（北京理工大学）；Centre for Quantum Physics, Key Laboratory of Advanced Optoelectronic Quantum Architecture and Measurement (MOE), School of Physics, Beijing Institute of Technology（北京理工大学物理学院先进光电量子架构与测量教育部重点实验室量子物理中心）；Beijing Key Laboratory of Quantum Matter State Control and Ultra-Precision Measurement Technology, Beijing Institute of Technology（北京理工大学量子物质态控制与超精密测量技术北京市重点实验室）；Quantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area（粤港澳大湾区量子科学中心）
Intricate magnetic landscape in antiferromagnetic kagome metal TbTi$_3$Bi$_4$ and interplay with Ln$_{2-x}$Ti$_{6+x}$Bi$_9$ (Ln: Tb-Lu) shurikagome metals
Ever since the experiments which founded the field of highly frustrated magnetism, the kagome Heisenberg antiferromagnet has been the archetypical setting for the study of fluctuation induced exotic ordering. To this day the nature of its classical low-temperature state has remained a mystery: the non-linear nature of the fluctuations around the exponentially numerous harmonically degenerate ground states has not permitted a controlled theory, while its complex energy landscape has precluded numerical simulations at low temperature. Here we present an efficient Monte Carlo algorithm which remo…
Chiral three-spin interactions can suppress long-range magnetic order and stabilize quantum spin liquid states in frustrated lattices. We study a spin-1/2 model on the kagome lattice involving a staggered three-spin interaction $J_χ$ in addition to Heisenberg exchange couplings $J_1$ on nearest-neighbor bonds and $J_d$ across the diagonals of the hexagons. We explore the phase diagram using a combination of a classical approach, parton mean-field theory, and variational Monte Carlo methods. We obtain a variety of noncoplanar magnetic orders, including a phase that interpolates between cuboc-1 …
The Heisenberg antiferromagnet on the kagome lattice is an archetypal instance of how large ground state degeneracies arise, and how they may get resolved by thermal and quantum fluctuations. Augmenting the Heisenberg model by chiral spin interactions has proved to be of particular interest in the discovery of certain chiral quantum spin liquids. Here we consider the classical variant of this chiral kagome model and find that it exhibits, similar to the classical Heisenberg antiferromagnet, a remarkably large and structured ground-state manifold, which combines continuous and discrete degrees …
We study the competition between $\sqrt{3} \times \sqrt{3}$ (RT3) and $q=0$ (Q0) magnetic orders in spin-one and spin-$3/2$ Kagome-lattice XXZ antiferromagnets with varying XY anisotropy parameter $Δ$, using series expansion methods. The Hamiltonian is split into two parts: an $H_0$ which favors the classical order in the desired pattern and an $H_1$, which is treated in perturbation theory by a series expansion. We find that the ground state energy series for the RT3 and Q0 phases are identical up to sixth order in the expansion, but ultimately a selection occurs, which depends on spin and th…
Owing to its unique geometry, the kagome lattice hosts various many-body quantum states including frustrated magnetism, superconductivity, and charge-density waves (CDWs), with intense efforts focused on kagome metals exhibiting $2\times2$ CDWs associated with the nesting of van Hove saddle points. Recently, a $\sqrt{3}\times\sqrt{3}$ CDW was discovered in the kagome metal ScV$_6$Sn$_6$ below $T_{\rm CDW}\approx91$~K, whose underlying mechanism and formation process remain unclear. Using inelastic X-ray scattering, we discover a short-range $\sqrt{3}\times\sqrt{3}\times2$ CDW that is dominant …
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）
The magnetic behavior of the compound, Gd3Ru4Al12, which has been reported to crystallize in a hexagonal structure about two decades ago, had not been investigated in the past literature despite interesting structural features (that is, magnetic layers and triangles as well as Kagome-lattice features favouring frustrated magnetism) characterizing this compound. We report here the results of magnetization, heat-capacity, and magnetoresistance studies in the temperature (T) range 1.8-300 K. The results establish that there is a long-range magnetic order of an antiferromagnetic type below (TN= ) …
Revealing Rotational Symmetry Breaking Charge-density Wave Order in Kagome Superconductor (Rb, K)V$_3$Sb$_5$ by Ultrafast Pump-probe Experiments
University of Pennsylvania（宾夕法尼亚大学）；Weizmann Institute of Science（魏茨曼科学研究所）；University of California Santa Barbara（加州大学圣巴巴拉分校）；Oak Ridge National Laboratory（橡树岭国家实验室）
Competition between Geometrical Frustration and the Kondo Effect in CePdAl Revealed by High-Resolution Magnetization
Institute for Solid State Physics, The University of Tokyo（东京大学固体物理研究所）；Nagoya Institute of Technology（名古屋工业大学）；Institute for Materials Research, Tohoku University（东北大学物质材料研究所）；School of Science and Engineering, Chuo University（中央理工学院）；Department of Basic Science, The University of Tokyo（东京大学基础科学系）；Graduate School of Science and Engineering, Univ. of Toyama（富山理工学研究院）
Structural and magnetic phases of topological kagome metal Fe$_3$Sn$_2$ under pressure
UGC-DAE Consortium for Scientific Research Mumbai Centre（UGC-DAE 科学研究联盟孟买中心）；Université Paris-Saclay（巴黎萨克雷大学）；CNRS, Laboratoire de Physique des Solides（法国国家科学研究中心固体物理实验室）；Uppsala University（乌普萨拉大学）；Bennett University（贝内特大学）；Indian Institute of Technology-Delhi（印度德里理工学院）；Synchrotron SOLEIL（索莱尔同步辐射中心）；Max Planck Institute for Chemical Physics of Solids（马克斯·普朗克固体化学物理研究所）；Institut universitaire de France (IUF)（法国高等研究院）
In this paper we report the impact of uniaxial strain $\varepsilon$ applied along the crystalline $a$ axis on the newly discovered kagome superconductor CsV$_3$Sb$_5$. At ambient conditions, CsV$_3$Sb$_5$ shows a charge-density wave (CDW) transition at $T_{\rm CDW}=94.5$ K and superconducts below $T_C = 3.34$ K. In our study, when the uniaxial strain $\varepsilon$ is varied from $-0.90\%$ to $0.90\%$, $T_C$ monotonically increases by $\sim 33\%$ from 3.0 K to 4.0 K, giving rise to the empirical relation $T_C (\varepsilon)=3.4+0.56\varepsilon+0.12\varepsilon^2$. On the other hand, for $\varepsi…
