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Singh K, Sihi A, Pandey SK, Mukherjee K. Evidence of charge susceptibility and multiple f- chybridization configurations with the La doping in CeGe: a DFT + DMFT study. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35. [PMID: 37161911 DOI: 10.1088/1361-648x/acd09a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/26/2023] [Indexed: 05/11/2023]
Abstract
Kondo coupling has been extensively investigated in several Ce-based systems. However, the search for materials showing the interplay between the Kondo effect, spin-orbit interaction, and crystal-field effect along with the presence of local charge susceptibility; remains a challenge for the condensed matter community. Actually, in Ce-based systems, the strong coupling of the conduction electrons to the local magnetic moments usually hides these properties. Here, we present a detailed investigation of Ce0.6La0.4Ge through a combined density functional theory and dynamic mean-field theory study. Our investigations give evidence of the significant charge susceptibility and the multiple differentf-chybridization configurations. The weakening of the magnetization owing to the dilution of the Ce-site is the main cause for the appearance of such properties, which is believed to occur due to the presence of the relevant local moment andf-chybridization over the competition with the on-site Coulomb interaction.
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Affiliation(s)
- Karan Singh
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075, Himachal Pradesh, India
| | - Antik Sihi
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075, Himachal Pradesh, India
| | - Sudhir K Pandey
- School of Mechanical and Materials Engineering, Indian Institute of Technology Mandi, Mandi 175075, Himachal Pradesh, India
| | - K Mukherjee
- School of Physical Sciences, Indian Institute of Technology Mandi, Mandi 175075, Himachal Pradesh, India
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2
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2021 White Paper on Recent Issues in Bioanalysis: ISR for Biomarkers, Liquid Biopsies, Spectral Cytometry, Inhalation/Oral & Multispecific Biotherapeutics, Accuracy/LLOQ for Flow Cytometry ( Part 2 - Recommendations on Biomarkers/CDx Assays Development & Validation, Cytometry Validation & Innovation, Biotherapeutics PK LBA Regulated Bioanalysis, Critical Reagents & Positive Controls Generation). Bioanalysis 2022; 14:627-692. [PMID: 35578974 DOI: 10.4155/bio-2022-0080] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The 15th edition of the Workshop on Recent Issues in Bioanalysis (15th WRIB) was held on 27 September to 1 October 2021. Even with a last-minute move from in-person to virtual, an overwhelmingly high number of nearly 900 professionals representing pharma and biotech companies, contract research organizations (CROs), and multiple regulatory agencies still eagerly convened to actively discuss the most current topics of interest in bioanalysis. The 15th WRIB included three Main Workshops and seven Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on biomarker assay development and validation (BAV) (focused on clarifying the confusion created by the increased use of the term "context of use" [COU]); mass spectrometry of proteins (therapeutic, biomarker and transgene); state-of-the-art cytometry innovation and validation; and critical reagent and positive control generation were the special features of the 15th edition. This 2021 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2021 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 2) covers the recommendations on ISR for Biomarkers, Liquid Biopsies, Spectral Cytometry, Inhalation/Oral & Multispecific Biotherapeutics, Accuracy/LLOQ for Flow Cytometry. Part 1A (Endogenous Compounds, Small Molecules, Complex Methods, Regulated Mass Spec of Large Molecules, Small Molecule, PoC), Part 1B (Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine) and Part 3 (TAb/NAb, Viral Vector CDx, Shedding Assays; CRISPR/Cas9 & CAR-T Immunogenicity; PCR & Vaccine Assay Performance; ADA Assay Comparability & Cut Point Appropriateness) are published in volume 14 of Bioanalysis, issues 9 and 11 (2022), respectively.
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Huang C, Zhang E, Zhang Y, Zhang J, Xiu F, Liu H, Xie X, Ai L, Yang Y, Zhao M, Qi J, Li L, Liu S, Li Z, Zhan R, Bie YQ, Kou X, Deng S, Xie XC. Observation of thickness-tuned universality class in superconducting β-W thin films. Sci Bull (Beijing) 2021; 66:1830-1838. [PMID: 36654392 DOI: 10.1016/j.scib.2021.05.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/23/2021] [Accepted: 05/24/2021] [Indexed: 01/20/2023]
Abstract
The interplay between quenched disorder and critical behavior in quantum phase transitions is conceptually fascinating and of fundamental importance for understanding phase transitions. However, it is still unclear whether or not the quenched disorder influences the universality class of quantum phase transitions. More crucially, the absence of superconducting-metal transitions under in-plane magnetic fields in 2D superconductors imposes constraints on the universality of quantum criticality. Here, we observe the thickness-tuned universality class of superconductor-metal transition by changing the disorder strength in β-W films with varying thickness. The finite-size scaling uncovers the switch of universality class: quantum Griffiths singularity to multiple quantum criticality at a critical thickness of tc⊥1~8nm and then from multiple quantum criticality to single criticality at tc⊥2~16nm. Moreover, the superconducting-metal transition is observed for the first time under in-plane magnetic fields and the universality class is changed at tc‖~8nm. The observation of thickness-tuned universality class under both out-of-plane and in-plane magnetic fields provides broad information for the disorder effect on superconducting-metal transitions and quantum criticality.
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Affiliation(s)
- Ce Huang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Enze Zhang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Yong Zhang
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Jinglei Zhang
- Anhui Province Key Laboratory of Condensed Matter Physics at ExtremeConditions, High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, China
| | - Faxian Xiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China; Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China; Shanghai Research Center for Quantum Sciences, Shanghai 201315, China.
| | - Haiwen Liu
- Center for Advanced Quantum Studies, Department of Physics, Beijing Normal University, Beijing 100875, China.
| | - Xiaoyi Xie
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Linfeng Ai
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Yunkun Yang
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Minhao Zhao
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Junjie Qi
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China
| | - Lun Li
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shanshan Liu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Zihan Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200433, China; Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201210, China
| | - Runze Zhan
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Ya-Qing Bie
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - Xufeng Kou
- School of Information Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Shaozhi Deng
- State Key Laboratory of Optoelectronic Materials and Technologies, Guangdong Province Key Laboratory of Display Material and Technology, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
| | - X C Xie
- Beijing Academy of Quantum Information Sciences, Beijing 100193, China; International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China; CAS Center for Excellence in Topological Quantum Computation, University of Chinese Academy of Sciences, Beijing 100190, China
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Fuhrman WT, Sidorenko A, Hänel J, Winkler H, Prokofiev A, Rodriguez-Rivera JA, Qiu Y, Blaha P, Si Q, Broholm CL, Paschen S. Pristine quantum criticality in a Kondo semimetal. SCIENCE ADVANCES 2021; 7:eabf9134. [PMID: 34138738 PMCID: PMC8133744 DOI: 10.1126/sciadv.abf9134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 03/30/2021] [Indexed: 06/12/2023]
Abstract
The observation of quantum criticality in diverse classes of strongly correlated electron systems has been instrumental in establishing ordering principles, discovering new phases, and identifying the relevant degrees of freedom and interactions. At focus so far have been insulators and metals. Semimetals, which are of great current interest as candidate phases with nontrivial topology, are much less explored in experiments. Here, we study the Kondo semimetal CeRu4Sn6 by magnetic susceptibility, specific heat, and inelastic neutron scattering experiments. The power-law divergence of the magnetic Grünesien ratio reveals that, unexpectedly, this compound is quantum critical without tuning. The dynamical energy over temperature scaling in the neutron response throughout the Brillouin zone and the temperature dependence of the static uniform susceptibility, indicate that temperature is the only energy scale in the criticality. Such behavior, which has been associated with Kondo destruction quantum criticality in metallic systems, could be generic in the semimetal setting.
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Affiliation(s)
- Wesley T Fuhrman
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Andrey Sidorenko
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Jonathan Hänel
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Hannes Winkler
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Andrey Prokofiev
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria
| | - Jose A Rodriguez-Rivera
- Department of Materials Sciences, University of Maryland, College Park, MD 20742, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Yiming Qiu
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Peter Blaha
- Institute of Materials Chemistry, Vienna University of Technology, 1040 Vienna, Austria
| | - Qimiao Si
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
| | - Collin L Broholm
- Institute for Quantum Matter and Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218, USA
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Department of Materials Science and Engineering, The Johns Hopkins University, Baltimore, MD 21218, USA
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, 1040 Vienna, Austria.
- Department of Physics and Astronomy, Rice Center for Quantum Materials, Rice University, Houston, TX 77005, USA
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5
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Weiland A, Wei K, McCandless GT, Baumbach RE, Chan JY. Fantastic n = 4: Ce 5Co 4+xGe 13-ySn y of the A n+1M nX 3n+1 homologous series. J Chem Phys 2021; 154:114707. [PMID: 33752369 DOI: 10.1063/5.0045015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Ce-based intermetallics are of interest due to the potential to study the interplay of localized magnetic moments and conduction electrons. Our work on Ce-based germanides led to the identification of a new homologous series An+1MnX3n+1 (A = rare earth, M = transition metal, X = tetrels, and n = 1-6). This work presents the single-crystal growth, structure determination, and anisotropic magnetic properties of the n = 4 member of the Cen+1ConGe3n+1 homologous series. Ce5Co4+xGe13-ySny consists of three Ce sites, three Co sites, seven Ge sites, and two Sn sites, and the crystal structure is best modeled in the orthorhombic space group Cmmm where a = 4.3031(8) Å, b = 45.608(13) Å, and c = 4.3264(8) Å, which is in close agreement with the previously reported Sn-free analog where a = 4.265(1) Å, b = 45.175(9) Å, and c = 4.293(3) Å. Anisotropic magnetic measurements show Kondo-like behavior and three magnetic transitions at 6, 4.9, and 2.4 K for Ce5Co4+xGe13-ySny.
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Affiliation(s)
- Ashley Weiland
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Kaya Wei
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Gregory T McCandless
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Ryan E Baumbach
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, USA
| | - Julia Y Chan
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, USA
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6
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Lv B, Chen J, Qiao L, Ma J, Yang X, Li M, Wang M, Tao Q, Xu ZA. Magnetic and transport properties of low-carrier-density Kondo semimetal CeSbTe. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:355601. [PMID: 31125978 DOI: 10.1088/1361-648x/ab2498] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Single crystals of CeSbTe with a ZrSiS-type structure were synthesized using vapor transport method. The stoichiometry is deviated from the nominal composition, which may cause some disorder in this compound. The physical properties were characterized by measuring the magnetic susceptibility, electrical resistivity, Hall resistivity and specific heat. One antiferromagnetic (AFM) transition related to Ce3+ ions was found at [Formula: see text] K, and a field-induced metamagnetic transition was observed below [Formula: see text]. The moderately enhanced Sommerfeld coefficient [Formula: see text] mJ mol-1 · K-2 and the estimated Kondo temperature [Formula: see text] K, indicate that CeSbTe is a moderately correlated AFM Kondo lattice compound with crystalline electric field effect. The carrier concentration of CeSbTe derived from the Hall coefficient is in the order of 1021 cm-3, lower than most Kondo metals, which indicates that CeSbTe is a low-carrier-density Kondo semimetal.
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Affiliation(s)
- Baijiang Lv
- Zhejiang Province Key Laboratory of Quantum Technology and Device, Department of Physics, Zhejiang University, Hangzhou 310027, People's Republic of China
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Heavy fermion quantum criticality at dilute carrier limit in CeNi 2-δ(As 1-xP x) 2. Sci Rep 2019; 9:12307. [PMID: 31444407 PMCID: PMC6707201 DOI: 10.1038/s41598-019-48662-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 08/07/2019] [Indexed: 12/03/2022] Open
Abstract
We study the quantum phase transitions in the nickel pnctides, CeNi2−δ(As1−xPx)2 (δ ≈ 0.07–0.22) polycrystalline samples. This series displays the distinct heavy fermion behavior in the rarely studied parameter regime of dilute carrier limit. We systematically investigate the magnetization, specific heat and electrical transport down to low temperatures. Upon increasing the P-content, the antiferromagnetic order of the Ce-4f moment is suppressed continuously and vanishes at xc ~ 0.55. At this doping, the temperature dependences of the specific heat and longitudinal resistivity display non-Fermi liquid behavior. Both the residual resistivity ρ0 and the Sommerfeld coefficient γ0 are sharply peaked around xc. When the P-content reaches close to 100%, we observe a clear low-temperature crossover into the Fermi liquid regime. In contrast to what happens in the parent compound x = 0.0 as a function of pressure, we find a surprising result that the non-Fermi liquid behavior persists over a nonzero range of doping concentration, xc < x < 0.9. In this doping range, at the lowest measured temperatures, the temperature dependence of the specific-heat coefficient is logarithmically divergent and that of the electrical resistivity is linear. We discuss the properties of CeNi2−δ(As1−xPx)2 in comparison with those of its 1111 counterpart, CeNi(As1−xPx)O. Our results indicate a non-Fermi liquid phase in the global phase diagram of heavy fermion metals.
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8
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Rai BK, H. Oswald IW, Ban W, Huang CL, Loganathan V, Hallas AM, Wilson MN, Luke GM, Harriger L, Huang Q, Li Y, Dzsaber S, Chan JY, Wang NL, Paschen S, Lynn JW, Nevidomskyy AH, Dai P, Si Q, Morosan E. Low-carrier density and fragile magnetism in a Kondo lattice system. PHYSICAL REVIEW. B 2019; 99:10.1103/PhysRevB.99.085120. [PMID: 38487214 PMCID: PMC10938852 DOI: 10.1103/physrevb.99.085120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/17/2024]
Abstract
Kondo-based semimetals and semiconductors are of extensive current interest as a viable platform for strongly correlated states in the dilute carrier limit. It is thus important to explore the routes to understand such systems. One established pathway is through the Kondo effect in metallic nonmagnetic analogs, in the so called half-filling case of one conduction electron and one 4f electron per site. Here, we demonstrate that Kondo-based semimetals develop out of conduction electrons with a low-carrier density in the presence of an even number of rare-earth sites. We do so by studying the Kondo material Yb3Ir4Ge13 along with its closed-4f -shell counterpart, Lu3Ir4Ge13. Through magnetotransport, optical conductivity, and thermodynamic measurements, we establish that the correlated semimetallic state of Yb3Ir4Ge13 below its Kondo temperature originates from the Kondo effect of a low-carrier conduction-electron background. In addition, it displays fragile magnetism at very low temperatures, which in turn, can be tuned to a Griffiths-phase-like regime through Lu-for-Yb substitution. These findings are connected with recent theoretical studies in simplified models. Our results can pave the way to exploring strong correlation physics in a semimetallic environment.
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Affiliation(s)
- Binod K. Rai
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Iain W. H. Oswald
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Wenjing Ban
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - C.-L. Huang
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - V. Loganathan
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - A. M. Hallas
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1
| | - M. N. Wilson
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1
| | - G. M. Luke
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1
- Canadian Institute for Advanced Research, 661 University Ave, Suite 505, Toronto, Ontario, Canada M5G 1M1
- TRIUMF, 4004 Wesbrook Mall, Vancouver, B.C., Canada V6T 2A3
| | - L. Harriger
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Q. Huang
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Y. Li
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Sami Dzsaber
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - Julia Y. Chan
- Department of Chemistry, University of Texas at Dallas, Richardson, Texas 75080, USA
| | - N. L. Wang
- International Center for Quantum Materials, School of Physics, Peking University, Beijing 100871, China
| | - Silke Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstrasse 8-10, 1040 Vienna, Austria
| | - J. W. Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Andriy H. Nevidomskyy
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Pengcheng Dai
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - Q. Si
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
| | - E. Morosan
- Department of Physics and Astronomy and Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
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Abstract
While electronic states with nontrivial topology have traditionally been known in insulators, they have been evidenced in metals during the past 2 years. Such Weyl semimetals show topological protection while conducting electricity both in the bulk and on the surface. An outstanding question is whether topological protection can happen in metals with strong correlations. Here, we report theoretical work on a strongly correlated lattice model to demonstrate the emergence of a Weyl–Kondo semimetal. We identify Weyl fermions in the bulk and Fermi arcs on the surface, both of which are associated with the many-body phenomenon called the Kondo effect. We determine a key signature of this Weyl–Kondo semimetal, which is realized in a recently discovered heavy-fermion compound. Insulating states can be topologically nontrivial, a well-established notion that is exemplified by the quantum Hall effect and topological insulators. By contrast, topological metals have not been experimentally evidenced until recently. In systems with strong correlations, they have yet to be identified. Heavy-fermion semimetals are a prototype of strongly correlated systems and, given their strong spin-orbit coupling, present a natural setting to make progress. Here, we advance a Weyl–Kondo semimetal phase in a periodic Anderson model on a noncentrosymmetric lattice. The quasiparticles near the Weyl nodes develop out of the Kondo effect, as do the surface states that feature Fermi arcs. We determine the key signatures of this phase, which are realized in the heavy-fermion semimetal Ce3Bi4Pd3. Our findings provide the much-needed theoretical foundation for the experimental search of topological metals with strong correlations and open up an avenue for systematic studies of such quantum phases that naturally entangle multiple degrees of freedom.
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10
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Dzsaber S, Prochaska L, Sidorenko A, Eguchi G, Svagera R, Waas M, Prokofiev A, Si Q, Paschen S. Kondo Insulator to Semimetal Transformation Tuned by Spin-Orbit Coupling. PHYSICAL REVIEW LETTERS 2017; 118:246601. [PMID: 28665644 DOI: 10.1103/physrevlett.118.246601] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Indexed: 06/07/2023]
Abstract
Recent theoretical studies of topologically nontrivial electronic states in Kondo insulators have pointed to the importance of spin-orbit coupling (SOC) for stabilizing these states. However, systematic experimental studies that tune the SOC parameter λ_{SOC} in Kondo insulators remain elusive. The main reason is that variations of (chemical) pressure or doping strongly influence the Kondo coupling J_{K} and the chemical potential μ-both essential parameters determining the ground state of the material-and thus possible λ_{SOC} tuning effects have remained unnoticed. Here, we present the successful growth of the substitution series Ce_{3}Bi_{4}(Pt_{1-x}Pd_{x})_{3} (0≤x≤1) of the archetypal (noncentrosymmetric) Kondo insulator Ce_{3}Bi_{4}Pt_{3}. The Pt-Pd substitution is isostructural, isoelectronic, and isosize, and it therefore is likely to leave J_{K} and μ essentially unchanged. By contrast, the large mass difference between the 5d element Pt and the 4d element Pd leads to a large difference in λ_{SOC}, which thus is the dominating tuning parameter in the series. Surprisingly, with increasing x (decreasing λ_{SOC}), we observe a Kondo insulator to semimetal transition, demonstrating an unprecedented drastic influence of the SOC. The fully substituted end compound Ce_{3}Bi_{4}Pd_{3} shows thermodynamic signatures of a recently predicted Weyl-Kondo semimetal.
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Affiliation(s)
- S Dzsaber
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - L Prochaska
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - A Sidorenko
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - G Eguchi
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - R Svagera
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - M Waas
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - A Prokofiev
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
| | - Q Si
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - S Paschen
- Institute of Solid State Physics, Vienna University of Technology, Wiedner Hauptstraße 8-10, 1040 Vienna, Austria
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
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11
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Weng ZF, Smidman M, Jiao L, Lu X, Yuan HQ. Multiple quantum phase transitions and superconductivity in Ce-based heavy fermions. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2016; 79:094503. [PMID: 27533524 DOI: 10.1088/0034-4885/79/9/094503] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Heavy fermions have served as prototype examples of strongly-correlated electron systems. The occurrence of unconventional superconductivity in close proximity to the electronic instabilities associated with various degrees of freedom points to an intricate relationship between superconductivity and other electronic states, which is unique but also shares some common features with high temperature superconductivity. The magnetic order in heavy fermion compounds can be continuously suppressed by tuning external parameters to a quantum critical point, and the role of quantum criticality in determining the properties of heavy fermion systems is an important unresolved issue. Here we review the recent progress of studies on Ce based heavy fermion superconductors, with an emphasis on the superconductivity emerging on the edge of magnetic and charge instabilities as well as the quantum phase transitions which occur by tuning different parameters, such as pressure, magnetic field and doping. We discuss systems where multiple quantum critical points occur and whether they can be classified in a unified manner, in particular in terms of the evolution of the Fermi surface topology.
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Affiliation(s)
- Z F Weng
- Center for Correlated Matter and Department of Physics, Zhejiang University, Hangzhou 310058, People's Republic of China
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