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Pan BY, Xu Y, Ni JM, Zhou SY, Hong XC, Qiu X, Li SY. Unambiguous Experimental Verification of Linear-in-Temperature Spinon Thermal Conductivity in an Antiferromagnetic Heisenberg Chain. PHYSICAL REVIEW LETTERS 2022; 129:167201. [PMID: 36306770 DOI: 10.1103/physrevlett.129.167201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 08/07/2022] [Accepted: 09/15/2022] [Indexed: 06/16/2023]
Abstract
The everlasting interest in spin chains is mostly rooted in the fact that they generally allow for comparisons between theory and experiment with remarkable accuracy, especially for exactly solvable models. A notable example is the spin-1/2 antiferromagnetic Heisenberg chain (AFHC), which can be well described by the Tomonaga-Luttinger liquid theory and exhibits fractionalized spinon excitations with distinct thermodynamic and spectroscopic experimental signatures consistent with theoretical predictions. A missing piece, however, is the lack of a comprehensive understanding of the spinon heat transport in AFHC systems, due to difficulties in its experimental evaluation against the backdrop of other heat carriers and complex scattering processes. Here we address this situation by performing ultralow-temperature thermal conductivity measurements on a nearly ideal spin-1/2 AFHC system copper benzoate Cu(C_{6}H_{5}COO)_{2}·3H_{2}O, whose field-dependent spin excitation gap enables a reliable extraction of the spinon thermal conductivity κ_{s} at zero field. κ_{s} was found to exhibit a linear temperature dependence κ_{s}∼T at low temperatures, with κ_{s}/T as large as 1.70 mW cm^{-1} K^{-2}, followed by a precipitate decline below ∼0.3 K. The observed κ_{s}∼T clarifies the discrepancies between various spin chain systems and serves as a benchmark for one-dimensional spinon heat transport in the low-temperature limit. The abrupt loss of κ_{s} with no corresponding anomaly in the specific heat is discussed in the context of many-body localization.
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Affiliation(s)
- B Y Pan
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
- School of Physics and Optoelectronic Engineering, Ludong University, Yantai, Shandong 264025, China
| | - Y Xu
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - J M Ni
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
| | - S Y Zhou
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
| | - X C Hong
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
| | - X Qiu
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
| | - S Y Li
- State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai 200438, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Shanghai Research Center for Quantum Sciences, Shanghai, 201315, China
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Huang YY, Xu Y, Wang L, Zhao CC, Tu CP, Ni JM, Wang LS, Pan BL, Fu Y, Hao Z, Liu C, Mei JW, Li SY. Heat Transport in Herbertsmithite: Can a Quantum Spin Liquid Survive Disorder? PHYSICAL REVIEW LETTERS 2021; 127:267202. [PMID: 35029499 DOI: 10.1103/physrevlett.127.267202] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 12/01/2021] [Indexed: 06/14/2023]
Abstract
One favorable situation for spins to enter the long-sought quantum spin liquid (QSL) state is when they sit on a kagome lattice. No consensus has been reached in theory regarding the true ground state of this promising platform. The experimental efforts, relying mostly on one archetypal material ZnCu_{3}(OH)_{6}Cl_{2}, have also led to diverse possibilities. Apart from subtle interactions in the Hamiltonian, there is the additional degree of complexity associated with disorder in the real material ZnCu_{3}(OH)_{6}Cl_{2} that haunts most experimental probes. Here we resort to heat transport measurement, a cleaner probe in which instead of contributing directly, the disorder only impacts the signal from the kagome spins. For ZnCu_{3}(OH)_{6}Cl_{2}, we observed no contribution by any spin excitation nor obvious field-induced change to the thermal conductivity. These results impose strong constraints on various scenarios about the ground state of this kagome compound: while certain quantum paramagnetic states other than a QSL may serve as natural candidates, a QSL state, gapless or gapped, must be dramatically modified by the disorder so that the kagome spin excitations are localized.
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Affiliation(s)
- Y Y Huang
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - Y Xu
- Key Laboratory of Polar Materials and Devices (MOE), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Le Wang
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - C C Zhao
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - C P Tu
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - J M Ni
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - L S Wang
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - B L Pan
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
| | - Ying Fu
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhanyang Hao
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Cai Liu
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jia-Wei Mei
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- Shenzhen Key Laboratory of Advanced Quantum Functional Materials and Devices, Southern University of Science and Technology, Shenzhen 518055, China
| | - S Y Li
- State Key Laboratory of Surface Physics, and Department of Physics, Fudan University, Shanghai 200438, China
- Collaborative Innovation Center of Advanced Microstructures, Nanjing 210093, China
- Shanghai Research Center for Quantum Sciences, Shanghai 201315, China
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Boulanger ME, Grissonnanche G, Badoux S, Allaire A, Lefrançois É, Legros A, Gourgout A, Dion M, Wang CH, Chen XH, Liang R, Hardy WN, Bonn DA, Taillefer L. Thermal Hall conductivity in the cuprate Mott insulators Nd 2CuO 4 and Sr 2CuO 2Cl 2. Nat Commun 2020; 11:5325. [PMID: 33087726 PMCID: PMC7577976 DOI: 10.1038/s41467-020-18881-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 09/17/2020] [Indexed: 12/04/2022] Open
Abstract
The heat carriers responsible for the unexpectedly large thermal Hall conductivity of the cuprate Mott insulator La2CuO4 were recently shown to be phonons. However, the mechanism by which phonons in cuprates acquire chirality in a magnetic field is still unknown. Here, we report a similar thermal Hall conductivity in two cuprate Mott insulators with significantly different crystal structures and magnetic orders – Nd2CuO4 and Sr2CuO2Cl2 – and show that two potential mechanisms can be excluded – the scattering of phonons by rare-earth impurities and by structural domains. Our comparative study further reveals that orthorhombicity, apical oxygens, the tilting of oxygen octahedra and the canting of spins out of the CuO2 planes are not essential to the mechanism of chirality. Our findings point to a chiral mechanism coming from a coupling of acoustic phonons to the intrinsic excitations of the CuO2 planes. What makes the phonons in cuprates become chiral, as measured by their thermal Hall effect, is an unresolved question. Here, the authors rule out two extrinsic mechanisms and argue that chirality comes from a coupling of acoustic phonons to the intrinsic excitations of the CuO2 planes.
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Affiliation(s)
- Marie-Eve Boulanger
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Gaël Grissonnanche
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Sven Badoux
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Andréanne Allaire
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Étienne Lefrançois
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Anaëlle Legros
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada.,SPEC, CEA, CNRS-UMR3680, Université Paris-Saclay, Gif-Sur-Yvette, France
| | - Adrien Gourgout
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Maxime Dion
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - C H Wang
- Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - X H Chen
- Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China, Hefei, Anhui, 230026, People's Republic of China
| | - R Liang
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - W N Hardy
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - D A Bonn
- Department of Physics & Astronomy, University of British Columbia, Vancouver, BC, V6T 1Z1, Canada
| | - Louis Taillefer
- Institut Quantique, Département de Physique & RQMP, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada. .,Canadian Institute for Advanced Research, Toronto, ON, M5G 1M1, Canada.
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Pientka F, Waissman J, Kim P, Halperin BI. Thermal Transport Signatures of Broken-Symmetry Phases in Graphene. PHYSICAL REVIEW LETTERS 2017; 119:027601. [PMID: 28753343 DOI: 10.1103/physrevlett.119.027601] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Indexed: 06/07/2023]
Abstract
In the half filled zero-energy Landau level of bilayer graphene, competing phases with spontaneously broken symmetries and an intriguing quantum critical behavior have been predicted. Here we investigate signatures of these broken-symmetry phases in thermal transport measurements. To this end, we calculate the spectrum of spin and valley waves in the ν=0 quantum Hall state of bilayer graphene. The presence of Goldstone modes enables heat transport even at low temperatures, which can serve as compelling evidence for spontaneous symmetry breaking. By varying external electric and magnetic fields, it is possible to determine the nature of the symmetry breaking. Temperature-dependent measurements may yield additional information about gapped modes.
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Affiliation(s)
- Falko Pientka
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Jonah Waissman
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Philip Kim
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Bertrand I Halperin
- Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA
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Leahy IA, Pocs CA, Siegfried PE, Graf D, Do SH, Choi KY, Normand B, Lee M. Anomalous Thermal Conductivity and Magnetic Torque Response in the Honeycomb Magnet α-RuCl_{3}. PHYSICAL REVIEW LETTERS 2017; 118:187203. [PMID: 28524686 DOI: 10.1103/physrevlett.118.187203] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Indexed: 06/07/2023]
Abstract
We report on the unusual behavior of the in-plane thermal conductivity κ and torque τ response in the Kitaev-Heisenberg material α-RuCl_{3}. κ shows a striking enhancement with linear growth beyond H=7 T, where magnetic order disappears, while τ for both of the in-plane symmetry directions shows an anomaly at the same field. The temperature and field dependence of κ are far more complex than conventional phonon and magnon contributions, and require us to invoke the presence of unconventional spin excitations whose properties are characteristic of a field-induced spin-liquid phase related to the enigmatic physics of the Kitaev model in an applied magnetic field.
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Affiliation(s)
- Ian A Leahy
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Christopher A Pocs
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Peter E Siegfried
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - David Graf
- National High Magnetic Field Laboratory, Tallahassee, Florida 32310, USA
| | - S-H Do
- Department of Physics, Chung-Ang University, Seoul 790-784, South Korea
| | - Kwang-Yong Choi
- Department of Physics, Chung-Ang University, Seoul 790-784, South Korea
| | - B Normand
- Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
| | - Minhyea Lee
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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Deng W, Chen X, Chen X, Liu Z, Zeng Y, Hu A, Xiong Y, Li Z, Tang Q. Alignment and structural control of nitrogen-doped carbon nanotubes by utilizing precursor concentration effect. NANOTECHNOLOGY 2014; 25:475601. [PMID: 25369800 DOI: 10.1088/0957-4484/25/47/475601] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Nitrogen-doped carbon nanotubes (NCNTs) were prepared using a simple ultrasonic spray pyrolysis method. The precursor concentration effect was examined to effectively control alignment, open tip and diameter of the NCNTs by changing xylene/cyclohexylamine ratio. The structure and morphology of the resultant NCNTs were characterized by scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy. The degree of alignment and the diameter of the NCNTs increased as the xylene/cyclohexylamine precursor mixture was changed from 0 to 35% cyclohexylamine. This precursor composition also caused a large number of open-ended nanotubes to form with graphite layers inside the cavities of the NCNTs. However, further increase cyclohexylamine content in the precursor reduced the degree of alignment and diameter of the NCNTs. We demonstrate control over the NCNT alignment and diameter, along with the formation of open-ended nanotube tips, and propose a growth mechanism to understand how these properties are interlinked.
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Affiliation(s)
- Weina Deng
- College of Materials Science and Engineering, Hunan Province Key Laboratory for Spray Deposition Technology and Application, Hunan University, Changsha 410082, People's Republic of China
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Pavlov VV, Pisarev RV, Gridnev VN, Zhukov EA, Yakovlev DR, Bayer M. Ultrafast optical pumping of spin and orbital polarizations in the antiferromagnetic Mott insulators R(2)CuO(4). PHYSICAL REVIEW LETTERS 2007; 98:047403. [PMID: 17358811 DOI: 10.1103/physrevlett.98.047403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2006] [Indexed: 05/14/2023]
Abstract
We demonstrate that optical pumping by circularly polarized light at the charge-transfer transition can induce spin and orbital polarizations in the strongly correlated Mott insulators R(2)CuO(4) (R=Pr, Nd, Sm) providing a means of ultrafast nonlinear manipulation of spin states on time scales of less than 150 fs. We propose a model which includes both orbital- and spin-related processes possessing different spectral and temporal properties. This allows us to model the optical response of antiferromagnetic Mott insulators to circularly polarized light and estimate the spin relaxation time as tau(s) approximately 30-50 fs.
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Affiliation(s)
- V V Pavlov
- A. F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, 194021 St. Petersburg, Russia
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Doiron-Leyraud N, Sutherland M, Li SY, Taillefer L, Liang R, Bonn DA, Hardy WN. Onset of a Boson mode at the superconducting critical point of underdoped YBa2Cu3Oy. PHYSICAL REVIEW LETTERS 2006; 97:207001. [PMID: 17155707 DOI: 10.1103/physrevlett.97.207001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Indexed: 05/12/2023]
Abstract
The thermal conductivity kappa of underdoped YBa2Cu3Oy was measured in the T-->0 limit as a function of hole concentration p across the superconducting critical point at pSC identical with 5.0%. The evolution of bosonic and fermionic contributions to kappa was tracked as the doping level evolved continuously in each of our samples. For p< or =pSC, we observe a T3 component in kappa which we attribute to the boson excitations of a phase with long-range spin or charge order. Fermionic transport, observed as a T-linear term in kappa which persists unaltered through pSC, violates the Wiedemann-Franz law, since the electrical resistivity varies as log(1/T) and grows with decreasing p.
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