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Siegfried PE, Bhandari H, Qi J, Ghimire R, Joshi J, Messegee ZT, Beeson WB, Liu K, Ghimire MP, Dang Y, Zhang H, Davydov AV, Tan X, Vora PM, Mazin II, Ghimire NJ. CoTe 2 : A Quantum Critical Dirac Metal with Strong Spin Fluctuations. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2300640. [PMID: 37012602 DOI: 10.1002/adma.202300640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Indexed: 05/26/2023]
Abstract
Quantum critical points separating weak ferromagnetic and paramagnetic phases trigger many novel phenomena. Dynamical spin fluctuations not only suppress the long-range order, but can also lead to unusual transport and even superconductivity. Combining quantum criticality with topological electronic properties presents a rare and unique opportunity. Here, by means of ab initio calculations and magnetic, thermal, and transport measurements, it is shown that the orthorhombic CoTe2 is close to ferromagnetism, which appears suppressed by spin fluctuations. Calculations and transport measurements reveal nodal Dirac lines, making it a rare combination of proximity to quantum criticality and Dirac topology.
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Affiliation(s)
- Peter E Siegfried
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Hari Bhandari
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Jeanie Qi
- Thomas Jefferson High School, Alexandria, VA, 22312, USA
| | - Rojila Ghimire
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, 44613, Nepal
| | - Jayadeep Joshi
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Zachary T Messegee
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA, 22030, USA
| | - Willie B Beeson
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Kai Liu
- Physics Department, Georgetown University, Washington, DC, 20057, USA
| | - Madhav Prasad Ghimire
- Central Department of Physics, Tribhuvan University, Kirtipur, Kathmandu, 44613, Nepal
| | - Yanliu Dang
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, 20899, USA
| | - Huairuo Zhang
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, 20899, USA
- Theiss Research, Inc., La Jolla, CA, 92037, USA
| | - Albert V Davydov
- Materials Science and Engineering Division, National Institute of Standards and Technology (NIST), Gaithersburg, Maryland, 20899, USA
| | - Xiaoyan Tan
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA, 22030, USA
| | - Patrick M Vora
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Igor I Mazin
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
| | - Nirmal J Ghimire
- Department of Physics and Astronomy, George Mason University, Fairfax, VA, 22030, USA
- Quantum Science and Engineering Center, George Mason University, Fairfax, VA, 22030, USA
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Abstract
Skyrmion, a concept originally proposed in particle physics half a century ago, can now find the most fertile field for its applicability, that is, the magnetic skyrmion realized in helimagnetic materials. The spin swirling vortex-like texture of the magnetic skyrmion can define the particle nature by topology; that is, all the constituent spin moments within the two-dimensional sheet wrap the sphere just one time. Such a topological nature of the magnetic skyrmion can lead to extraordinary metastability via topological protection and the driven motion with low electric-current excitation, which may promise future application to spintronics. The skyrmions in the magnetic materials frequently show up as the crystal lattice form, e.g., hexagonal lattice, but sometimes as isolated or independent particles. These skyrmions in magnets were initially found in acentric magnets, such as chiral, polar, and bilayered magnets endowed with antisymmetric spin exchange interaction, while the skyrmion host materials have been explored in a broader family of compounds including centrosymmetric magnets. This review describes the materials science and materials chemistry of magnetic skyrmions using the classification scheme of the skyrmion forming microscopic mechanisms. The emergent phenomena and functions mediated by skyrmions are described, including the generation of emergent magnetic and electric field by statics and dynamics of skrymions and the inherent magnetoelectric effect. The other important magnetic topological defects in two or three dimensions, such as biskyrmions, antiskyrmions, merons, and hedgehogs, are also reviewed in light of their interplay with the skyrmions.
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Affiliation(s)
- Yoshinori Tokura
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan.,RIKEN Center for Emergent Matter Science (CEMS), Wako, 351-0198, Japan.,Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - Naoya Kanazawa
- Department of Applied Physics, University of Tokyo, Tokyo 113-8656, Japan
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Karube K, White JS, Morikawa D, Dewhurst CD, Cubitt R, Kikkawa A, Yu X, Tokunaga Y, Arima TH, Rønnow HM, Tokura Y, Taguchi Y. Disordered skyrmion phase stabilized by magnetic frustration in a chiral magnet. SCIENCE ADVANCES 2018; 4:eaar7043. [PMID: 30225364 PMCID: PMC6140611 DOI: 10.1126/sciadv.aar7043] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 08/03/2018] [Indexed: 05/23/2023]
Abstract
Magnetic skyrmions are vortex-like topological spin textures often observed to form a triangular-lattice skyrmion crystal in structurally chiral magnets with the Dzyaloshinskii-Moriya interaction. Recently, β-Mn structure-type Co-Zn-Mn alloys were identified as a new class of chiral magnet to host such skyrmion crystal phases, while β-Mn itself is known as hosting an elemental geometrically frustrated spin liquid. We report the intermediate composition system Co7Zn7Mn6 to be a unique host of two disconnected, thermal-equilibrium topological skyrmion phases; one is a conventional skyrmion crystal phase stabilized by thermal fluctuations and restricted to exist just below the magnetic transition temperature Tc, and the other is a novel three-dimensionally disordered skyrmion phase that is stable well below Tc. The stability of this new disordered skyrmion phase is due to a cooperative interplay between the chiral magnetism with the Dzyaloshinskii-Moriya interaction and the frustrated magnetism inherent to β-Mn.
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Affiliation(s)
- Kosuke Karube
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Jonathan S. White
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen, Switzerland
| | | | - Charles D. Dewhurst
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Robert Cubitt
- Institut Laue-Langevin, 71 Avenue des Martyrs, CS 20156, 38042 Grenoble Cedex 9, France
| | - Akiko Kikkawa
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Xiuzhen Yu
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
| | - Yusuke Tokunaga
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Taka-hisa Arima
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Advanced Materials Science, University of Tokyo, Kashiwa 277-8561, Japan
| | - Henrik M. Rønnow
- Laboratory for Quantum Magnetism, Institute of Physics, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Yoshinori Tokura
- RIKEN Center for Emergent Matter Science, Wako 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Bunkyo-ku 113-8656, Japan
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Aston JC, Saines PJ. Transition-Metal Dependent Cation Disorder in the Chiral CubicAB(HCO2)3Metal-Organic Frameworks (A= Li or Na,B= Mn or Co). Z Anorg Allg Chem 2017. [DOI: 10.1002/zaac.201600350] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- James C. Aston
- School of Physical Sciences; University of Kent; Ingram Building CT2 7NH Canterbury United Kingdom
| | - Paul J. Saines
- School of Physical Sciences; University of Kent; Ingram Building CT2 7NH Canterbury United Kingdom
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5
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He H, Miiller W, Aronson MC. New Kagome Metal Sc3Mn3Al7Si5 and Its Gallium-Doped Analogues: Synthesis, Crystal Structure, and Physical Properties. Inorg Chem 2014; 53:9115-21. [DOI: 10.1021/ic501088t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Hua He
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
| | - Wojciech Miiller
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
| | - Meigan C. Aronson
- Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794, United States
- Condensed
Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, New York 11973, United States
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Paddison JAM, Stewart JR, Manuel P, Courtois P, McIntyre GJ, Rainford BD, Goodwin AL. Emergent frustration in co-doped β-Mn. PHYSICAL REVIEW LETTERS 2013; 110:267207. [PMID: 23848920 DOI: 10.1103/physrevlett.110.267207] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 03/26/2013] [Indexed: 06/02/2023]
Abstract
We investigate low-temperature spin correlations in the metallic frustrated magnet β-Mn1-xCox. Single-crystal polarized-neutron scattering experiments reveal the persistence of highly structured magnetic diffuse scattering and the absence of periodic magnetic order to T=0.05 K. We employ reverse Monte Carlo refinements and mean-field theory calculations to construct an effective Hamiltonian which accounts for the magnetic scattering. The interactions we identify describe an emergent spin structure which mimics the triangular lattice antiferromagnet, one of the canonical models of frustrated magnetism.
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Affiliation(s)
- Joseph A M Paddison
- Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, United Kingdom
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Khan AU, Rogl G, Kriegisch M, Michor H, Müller H, Bauer E, Grytsiv A, Giester G, Rogl P. Ti8(Ti(x)Mn(1-x))6Mn39 ('TiMn(~4)'): a metallic spin fluctuation system. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2013; 25:106002. [PMID: 23389037 DOI: 10.1088/0953-8984/25/10/106002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The crystal structure of Ti(8)(Ti(x)Mn(1-x))(6)Mn(39), x = 0.187, was obtained from x-ray single-crystal diffraction data, confirming it to have rhombohedral symmetry (space group [Formula: see text]; a(hex) = 1.100 70(2) nm, c(hex) = 1.944 11(4) nm; R(F) = 0.0293) and isotypism with the prototype Mo(0.38)Cr(0.16)Co(0.46) (the so-called R-phase). On the basis of electron probe micro-analyser results and structure determination, the homogeneity region of the phase TiMn(~4) was determined for temperatures in the range 800 °C < T < 1200 °C and is in between 16.0 at.% Ti and 20 at.% Ti. Various physical properties, determined in the temperature range from ~2 K to room temperature, characterize the compound with composition TiMn(4.26) as a metallic spin fluctuation system, evidenced from a T(3)lnT dependence of the heat capacity in combination with large values of the electronic Sommerfeld constant of the order of 140 mJ mol(-1) K(-2). The occurrence of a small anomaly in the heat capacity and magnetization data around 10 K is attributed to a scenario involving spin freezing phenomena, since a fraction of the order of 10% of all Mn-Mn distances within the unit cell are above a critical distance, where Mn atoms carry a spontaneous magnetic moment.
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Affiliation(s)
- Atta U Khan
- Institute of Physical Chemistry, University of Vienna, Währingerstrasse 42, A-1090 Wien, Austria
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Stewart JR, Cywinski R. Magnetic short-range order in β-Mn(1-x)Co(x). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:124216. [PMID: 21817458 DOI: 10.1088/0953-8984/21/12/124216] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a study of the magnetic ground state properties of β-Mn metal alloyed with Co, using neutron polarization analysis of the diffuse neutron scattering cross-section. We analyse the magnetic structure obtained using a reverse Monte Carlo procedure to extract the Mn-Mn spin correlations. The addition of Co leads to a static disordered magnetic structure with medium-range correlations. Our analysis of the spin correlations indicates that both 8c and 12d non-equivalent lattice sites present in the β-Mn structure contribute to the magnetic ground state, where previously it was thought that the 8c site was non-magnetic.
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Affiliation(s)
- J R Stewart
- ISIS, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX, UK
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Krimmel A, Mücksch M, Tsurkan V, Koza MM, Mutka H, Loidl A. Vibronic and magnetic excitations in the spin-orbital liquid state of FeSc2S4. PHYSICAL REVIEW LETTERS 2005; 94:237402. [PMID: 16090501 DOI: 10.1103/physrevlett.94.237402] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2004] [Indexed: 05/03/2023]
Abstract
Inelastic neutron scattering results on the spin-orbital liquid in FeSc2S4 are presented. This sulfospinel reveals strong geometric frustration in the spin and in the orbital sector. In the present experiments the orbital liquid is evidenced by a clear spectroscopic signature of a dynamic Jahn-Teller effect with a vibronic splitting 3Gamma approximately 2 meV in agreement with theoretical estimates. The excitations of the spin liquid reveal strong dispersion and can be characterized as cooperative spin excitations in a supercooled paramagnet with a spin gap of Delta approximately 0.2 meV.
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Affiliation(s)
- A Krimmel
- Experimentalphysik V, Center for Electronic Correlations and Magnetism, Universität Augsburg, D-86159 Augsburg, Germany
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