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Ye L, Sun Y, Sunko V, Rodriguez-Nieva JF, Ikeda MS, Worasaran T, Sorensen ME, Bachmann MD, Orenstein J, Fisher IR. Elastocaloric signatures of symmetric and antisymmetric strain-tuning of quadrupolar and magnetic phases in DyB 2C 2. Proc Natl Acad Sci U S A 2023; 120:e2302800120. [PMID: 37607225 PMCID: PMC10468613 DOI: 10.1073/pnas.2302800120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 07/22/2023] [Indexed: 08/24/2023] Open
Abstract
The adiabatic elastocaloric effect measures the temperature change of a given system with strain and provides a thermodynamic probe of the entropic landscape in the temperature-strain space. Here, we demonstrate that the DC bias strain-dependence of AC elastocaloric effect allows decomposition of the latter into symmetric (rotation-symmetry-preserving) and antisymmetric (rotation-symmetry-breaking) strain channels, using a tetragonal [Formula: see text]-electron intermetallic DyB[Formula: see text]C[Formula: see text]-whose antiferroquadrupolar order breaks local fourfold rotational symmetries while globally remaining tetragonal-as a showcase example. We capture the strain evolution of its quadrupolar and magnetic phase transitions using both singularities in the elastocaloric coefficient and its jumps at the transitions, and the latter we show follows a modified Ehrenfest relation. We find that antisymmetric strain couples to the underlying order parameter in a biquadratic (linear-quadratic) manner in the antiferroquadrupolar (canted antiferromagnetic) phase, which are attributed to a preserved (broken) global tetragonal symmetry, respectively. The broken tetragonal symmetry in the magnetic phase is further evidenced by elastocaloric strain-hysteresis and optical birefringence. Additionally, within the staggered quadrupolar order, the observed elastocaloric response reflects a quadratic increase of entropy with antisymmetric strain, analogous to the role magnetic field plays for Ising antiferromagnetic orders by promoting pseudospin flips. Our results demonstrate AC elastocaloric effect as a compact and incisive thermodynamic probe into the coupling between electronic degrees of freedom and strain in free energy, which holds the potential for investigating and understanding the symmetry of a wide variety of ordered phases in broader classes of quantum materials.
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Affiliation(s)
- Linda Ye
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
| | - Yue Sun
- Department of Physics, University of California, Berkeley, CA94720
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | - Veronika Sunko
- Department of Physics, University of California, Berkeley, CA94720
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | | | - Matthias S. Ikeda
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
| | - Thanapat Worasaran
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
| | - Matthew E. Sorensen
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Physics, Stanford University, Stanford, CA94305
| | - Maja D. Bachmann
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, CA94720
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | - Ian R. Fisher
- Geballe Laboratory for Advanced Materials, Stanford University, Stanford, CA94305
- Department of Applied Physics, Stanford University, Stanford, CA94305
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Lee C, Sun Y, Ye L, Rathi S, Wang K, Lu YM, Moore J, Checkelsky JG, Orenstein J. Spin wavepackets in the Kagome ferromagnet Fe 3Sn 2: Propagation and precursors. Proc Natl Acad Sci U S A 2023; 120:e2220589120. [PMID: 37186856 DOI: 10.1073/pnas.2220589120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
The propagation of spin waves in magnetically ordered systems has emerged as a potential means to shuttle quantum information over large distances. Conventionally, the arrival time of a spin wavepacket at a distance, d, is assumed to be determined by its group velocity, vg. Here, we report time-resolved optical measurements of wavepacket propagation in the Kagome ferromagnet Fe3Sn2 that demonstrate the arrival of spin information at times significantly less than d/vg. We show that this spin wave "precursor" originates from the interaction of light with the unusual spectrum of magnetostatic modes in Fe3Sn2. Related effects may have far-reaching consequences toward realizing long-range, ultrafast spin wave transport in both ferromagnetic and antiferromagnetic systems.
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Affiliation(s)
- Changmin Lee
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, Hanyang University, Seoul 04763, Republic of Korea
| | - Yue Sun
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
| | - Linda Ye
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Sumedh Rathi
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
| | - Kevin Wang
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
| | - Yuan-Ming Lu
- Department of Physics, The Ohio State University, Columbus, OH 43210
| | - Joel Moore
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
| | - Joseph G Checkelsky
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Joseph Orenstein
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720
- Department of Physics, University of California, Berkeley, CA 94720
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Lee C, Vir P, Manna K, Shekhar C, Moore JE, Kastner MA, Felser C, Orenstein J. Observation of a phase transition within the domain walls of ferromagnetic Co3Sn2S2. Nat Commun 2022; 13:3000. [PMID: 35637177 PMCID: PMC9151713 DOI: 10.1038/s41467-022-30460-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 05/01/2022] [Indexed: 11/09/2022] Open
Abstract
AbstractThe ferromagnetic phase of Co3Sn2S2 is widely considered to be a topological Weyl semimetal, with evidence for momentum-space monopoles of Berry curvature from transport and spectroscopic probes. As the bandstructure is highly sensitive to the magnetic order, attention has focused on anomalies in magnetization, susceptibility and transport measurements that are seen well below the Curie temperature, leading to speculation that a “hidden” phase coexists with ferromagnetism. Here we report spatially-resolved measurements by Kerr effect microscopy that identify this phase. We find that the anomalies coincide with a deep minimum in domain wall (DW) mobility, indicating a crossover between two regimes of DW propagation. We demonstrate that this crossover is a manifestation of a 2D phase transition that occurs within the DW, in which the magnetization texture changes from continuous rotation to unidirectional variation. We propose that the existence of this 2D transition deep within the ferromagnetic state of the bulk is a consequence of a giant quality factor for magnetocrystalline anisotropy unique to this compound. This work broadens the horizon of the conventional binary classification of DWs into Bloch and Néel walls, and suggests new strategies for manipulation of domain walls and their role in electron and spin transport.
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Rees D, Lu B, Sun Y, Manna K, Özgür R, Subedi S, Borrmann H, Felser C, Orenstein J, Torchinsky DH. Direct Measurement of Helicoid Surface States in RhSi Using Nonlinear Optics. Phys Rev Lett 2021; 127:157405. [PMID: 34678039 DOI: 10.1103/physrevlett.127.157405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/02/2021] [Accepted: 09/15/2021] [Indexed: 06/13/2023]
Abstract
Despite the fundamental nature of the edge state in topological physics, direct measurement of electronic and optical properties of the Fermi arcs of topological semimetals has posed a significant experimental challenge, as their response is often overwhelmed by the metallic bulk. However, laser-driven currents carried by surface and bulk states can propagate in different directions in nonsymmorphic crystals, allowing for the two components to be easily separated. Motivated by a recent theoretical prediction G. Chang et al., Phys. Rev. Lett. 124, 166404 (2020)PRLTAO0031-900710.1103/PhysRevLett.124.166404, we have measured the linear and circular photogalvanic effect currents deriving from the Fermi arcs of the nonsymmorphic, chiral Weyl semimetal RhSi over the 0.45-1.1 eV incident photon energy range. Our data are in good agreement with the predicted spectral shape of the circular photogalvanic effect as a function of photon energy, although the direction of the surface photocurrent departed from the theoretical expectation over the energy range studied. Surface currents arising from the linear photogalvanic effect were observed as well, with the unexpected result that only two of the six allowed tensor element were required to describe the measurements, suggesting an approximate emergent mirror symmetry inconsistent with the space group of the crystal.
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Affiliation(s)
- Dylan Rees
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Baozhu Lu
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Yue Sun
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, USA
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
- Department of Physics, Indian Institute of Technology Delhi, New Delhi 110016, India
| | - Rüstem Özgür
- Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA
| | - Sujan Subedi
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - J Orenstein
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Darius H Torchinsky
- Department of Physics, Temple University, Philadelphia, Pennsylvania 19122, USA
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Hain E, Adejumo H, Anger B, Orenstein J, Blaney L. Advances in antimicrobial activity analysis of fluoroquinolone, macrolide, sulfonamide, and tetracycline antibiotics for environmental applications through improved bacteria selection. J Hazard Mater 2021; 415:125686. [PMID: 34088184 DOI: 10.1016/j.jhazmat.2021.125686] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Revised: 02/13/2021] [Accepted: 03/16/2021] [Indexed: 06/12/2023]
Abstract
The widespread use of antibiotics has led to their ubiquitous presence in water and wastewater and raised concerns about antimicrobial resistance. Clinical antibiotic susceptibility assays have been repurposed to measure removal of antimicrobial activity during water and wastewater treatment processes. The corresponding protocols have mainly employed growth inhibition of Escherichia coli. The present work focused on optimizing bacteria selection to improve the sensitivity of residual antimicrobial activity measurements by broth microdilution assays. Thirteen antibiotics from four classes (i.e., fluoroquinolones, macrolides, sulfonamides, tetracyclines) were investigated against three gram-negative organisms, namely E. coli, Mycoplasma microti, and Pseudomonas fluorescens. The minimum inhibitory concentration (MIC) and half-maximal inhibitory concentration (IC50) were calculated for each antibiotic-bacteria pair. P. fluorescens produces a fluorescent siderophore, pyoverdine, that was used to assess sublethal effects and further enhance the sensitivity of antimicrobial activity measurements. The optimal antibiotic-bacteria pairs were as follows: fluoroquinolone-E. coli (growth inhibition); macrolide- and sulfonamide-M. microti (growth inhibition); and, tetracycline-P. fluorescens (pyoverdine inhibition). Compared to E. coli growth inhibition, the sensitivity of antimicrobial activity analysis was improved by up to 728, 19, and 2.7 times for macrolides (tylosin), sulfonamides (sulfamethoxazole), and tetracyclines (chlortetracycline), facilitating application of these bioassays at environmentally-relevant conditions.
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Affiliation(s)
- Ethan Hain
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Hollie Adejumo
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA; University of Michigan, Department of Civil and Environmental Engineering, 2350 Hayward Street, 2105 GG Brown Building, Ann Arbor, MI 48109-2125, USA
| | - Bridget Anger
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Joseph Orenstein
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA
| | - Lee Blaney
- University of Maryland Baltimore County, Department of Chemical, Biochemical, and Environmental Engineering, 1000 Hilltop Circle, Engineering 314, Baltimore, MD 21250, USA.
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Little A, Lee C, John C, Doyle S, Maniv E, Nair NL, Chen W, Rees D, Venderbos JWF, Fernandes RM, Analytis JG, Orenstein J. Three-state nematicity in the triangular lattice antiferromagnet Fe 1/3NbS 2. Nat Mater 2020; 19:1062-1067. [PMID: 32424369 DOI: 10.1038/s41563-020-0681-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
Nematic order is the breaking of rotational symmetry in the presence of translational invariance. While originally defined in the context of liquid crystals, the concept of nematic order has arisen in crystalline matter with discrete rotational symmetry, most prominently in the tetragonal Fe-based superconductors where the parent state is four-fold symmetric. In this case the nematic director takes on only two directions, and the order parameter in such 'Ising-nematic' systems is a simple scalar. Here, using a spatially resolved optical polarimetry technique, we show that a qualitatively distinct nematic state arises in the triangular lattice antiferromagnet Fe1/3NbS2. The crucial difference is that the nematic order on the triangular lattice is a [Formula: see text] or three-state Potts-nematic order parameter. As a consequence, the anisotropy axes of response functions such as the resistivity tensor can be continuously reoriented by external perturbations. This discovery lays the groundwork for devices that exploit analogies with nematic liquid crystals.
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Affiliation(s)
- Arielle Little
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Changmin Lee
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Caolan John
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Spencer Doyle
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Nityan L Nair
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Wenqin Chen
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Dylan Rees
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Jörn W F Venderbos
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA, USA
- Department of Physics, Drexel University, Philadelphia, PA, USA
| | - Rafael M Fernandes
- School of Physics and Astronomy, University of Minnesota, Minneapolis, MN, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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7
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Nair NL, Maniv E, John C, Doyle S, Orenstein J, Analytis JG. Author Correction: Electrical switching in a magnetically intercalated transition metal dichalcogenide. Nat Mater 2020; 19:1036. [PMID: 32704158 DOI: 10.1038/s41563-020-0776-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- Nityan L Nair
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Caolan John
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Spencer Doyle
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J Orenstein
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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Rees D, Manna K, Lu B, Morimoto T, Borrmann H, Felser C, Moore JE, Torchinsky DH, Orenstein J. Helicity-dependent photocurrents in the chiral Weyl semimetal RhSi. Sci Adv 2020; 6:eaba0509. [PMID: 32832618 PMCID: PMC7439497 DOI: 10.1126/sciadv.aba0509] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/29/2020] [Indexed: 05/02/2023]
Abstract
Weyl semimetals are crystals in which electron bands cross at isolated points in momentum space. Associated with each crossing point (or Weyl node) is a topological invariant known as the Berry monopole charge. The circular photogalvanic effect (CPGE), whereby circular polarized light generates a helicity-dependent photocurrent, is a notable example of a macroscopic property that emerges directly from the topology of the Weyl semimetal band structure. Recently, it was predicted that the amplitude of the CPGE associated with optical transitions near a Weyl node is proportional to its monopole charge. In chiral Weyl systems, nodes of opposite charge are nondegenerate, opening a window of wavelengths where the CPGE resulting from uncompensated Berry charge can emerge. Here, we report measurements of CPGE in the chiral Weyl semimetal RhSi, revealing a CPGE response in an energy window that closes at 0.65 eV, in agreement with the predictions of density functional theory.
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Affiliation(s)
- Dylan Rees
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Kaustuv Manna
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Baozhu Lu
- Department of Physics, Temple University, Philadelphia, PA 19122, USA
| | - Takahiro Morimoto
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan
| | - Horst Borrmann
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - Claudia Felser
- Max Planck Institute for Chemical Physics of Solids, Dresden D-01187, Germany
| | - J. E. Moore
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Darius H. Torchinsky
- Department of Physics, Temple University, Philadelphia, PA 19122, USA
- Corresponding author. (D.H.T.); (J.O.)
| | - J. Orenstein
- Department of Physics, University of California, Berkeley, Berkeley, CA 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
- Corresponding author. (D.H.T.); (J.O.)
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Nair NL, Maniv E, John C, Doyle S, Orenstein J, Analytis JG. Publisher Correction: Electrical switching in a magnetically intercalated transition metal dichalcogenide. Nat Mater 2020; 19:474. [PMID: 31723257 DOI: 10.1038/s41563-019-0553-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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Affiliation(s)
- Nityan L Nair
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Caolan John
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Spencer Doyle
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J Orenstein
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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10
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Nair NL, Maniv E, John C, Doyle S, Orenstein J, Analytis JG. Electrical switching in a magnetically intercalated transition metal dichalcogenide. Nat Mater 2020; 19:153-157. [PMID: 31685945 DOI: 10.1038/s41563-019-0518-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 09/19/2019] [Indexed: 06/10/2023]
Abstract
Advances in controlling the correlated behaviour of transition metal dichalcogenides have opened a new frontier of many-body physics in two dimensions. A field where these materials have yet to make a deep impact is antiferromagnetic spintronics-a relatively new research direction promising technologies with fast switching times, insensitivity to magnetic perturbations and reduced cross-talk1-3. Here, we present measurements on the intercalated transition metal dichalcogenide Fe1/3NbS2 that exhibits antiferromagnetic ordering below 42 K (refs. 4,5). We find that remarkably low current densities of the order of 104 A cm-2 can reorient the magnetic order, which can be detected through changes in the sample resistance, demonstrating its use as an electronically accessible antiferromagnetic switch. Fe1/3NbS2 is part of a larger family of magnetically intercalated transition metal dichalcogenides, some of which may exhibit switching at room temperature, forming a platform from which to build tuneable antiferromagnetic spintronic devices6,7.
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Affiliation(s)
- Nityan L Nair
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Eran Maniv
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Caolan John
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Spencer Doyle
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - J Orenstein
- Department of Physics, University of California, Berkeley, CA, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, CA, USA.
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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11
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Thewalt E, Hayes IM, Hinton JP, Little A, Patankar S, Wu L, Helm T, Stan CV, Tamura N, Analytis JG, Orenstein J. Imaging Anomalous Nematic Order and Strain in Optimally Doped BaFe_{2}(As,P)_{2}. Phys Rev Lett 2018; 121:027001. [PMID: 30085755 DOI: 10.1103/physrevlett.121.027001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Indexed: 06/08/2023]
Abstract
We present the strain and temperature dependence of an anomalous nematic phase in optimally doped BaFe_{2}(As,P)_{2}. Polarized ultrafast optical measurements reveal broken fourfold rotational symmetry in a temperature range above T_{c} in which bulk probes do not detect a phase transition. Using ultrafast microscopy, we find that the magnitude and sign of this nematicity vary on a 50-100 μm length scale, and the temperature at which it onsets ranges from 40 K near a domain boundary to 60 K deep within a domain. Scanning Laue microdiffraction maps of local strain at room temperature indicate that the nematic order appears most strongly in regions of weak, isotropic strain. These results indicate that nematic order arises in a genuine phase transition rather than by enhancement of local anisotropy by a strong nematic susceptibility. We interpret our results in the context of a proposed surface nematic phase.
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Affiliation(s)
- Eric Thewalt
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Ian M Hayes
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James P Hinton
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Arielle Little
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Shreyas Patankar
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Liang Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Toni Helm
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Camelia V Stan
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Nobumichi Tamura
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - James G Analytis
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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12
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Higo T, Man H, Gopman DB, Wu L, Koretsune T, van ’t Erve OMJ, Kabanov YP, Rees D, Li Y, Suzuki MT, Patankar S, Ikhlas M, Chien CL, Arita R, Shull RD, Orenstein J, Nakatsuji S. Large magneto-optical Kerr effect and imaging of magnetic octupole domains in an antiferromagnetic metal. Nat Photonics 2018; 12:73-78. [PMID: 29910828 PMCID: PMC5997294 DOI: 10.1038/s41566-017-0086-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 12/13/2017] [Indexed: 05/15/2023]
Abstract
When a polarized light beam is incident upon the surface of a magnetic material, the reflected light undergoes a polarization rotation1. This magneto-optical Kerr effect (MOKE) has been intensively studied in a variety of ferro- and ferrimagnetic materials because it provides a powerful probe for electronic and magnetic properties2, 3 as well as for various applications including magneto-optical recording4. Recently, there has been a surge of interest in antiferromagnets (AFMs) as prospective spintronic materials for high-density and ultrafast memory devices, owing to their vanishingly small stray field and orders of magnitude faster spin dynamics compared to their ferromagnetic counterparts5-9. In fact, the MOKE has proven useful for the study and application of the antiferromagnetic (AF) state. Although limited to insulators, certain types of AFMs are known to exhibit a large MOKE, as they are weak ferromagnets due to canting of the otherwise collinear spin structure10-14. Here we report the first observation of a large MOKE signal in an AF metal at room temperature. In particular, we find that despite a vanishingly small magnetization of M ~0.002 µB/Mn, the non-collinear AF metal Mn3Sn15 exhibits a large zero-field MOKE with a polar Kerr rotation angle of 20 milli-degrees, comparable to ferromagnetic metals. Our first-principles calculations have clarified that ferroic ordering of magnetic octupoles in the non-collinear Néel state16 may cause a large MOKE even in its fully compensated AF state without spin magnetization. This large MOKE further allows imaging of the magnetic octupole domains and their reversal induced by magnetic field. The observation of a large MOKE in an AF metal should open new avenues for the study of domain dynamics as well as spintronics using AFMs.
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Affiliation(s)
- Tomoya Higo
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - Huiyuan Man
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
| | - Daniel B. Gopman
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Liang Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Takashi Koretsune
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
- Department of Physics, Tohoku University, Sendai, Miyagi 980-8578, Japan
- RIKEN-CEMS, Wako, Saitama 351-0198, Japan
| | - Olaf M. J. van ’t Erve
- Materials Science and Technology Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - Yury P. Kabanov
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka, Moscow Region 142432, Russia
| | - Dylan Rees
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Yufan Li
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Michi-To Suzuki
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
- RIKEN-CEMS, Wako, Saitama 351-0198, Japan
| | - Shreyas Patankar
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Muhammad Ikhlas
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
| | - C. L. Chien
- Department of Physics and Astronomy, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ryotaro Arita
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
- RIKEN-CEMS, Wako, Saitama 351-0198, Japan
| | - Robert D. Shull
- Materials Science and Engineering Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Satoru Nakatsuji
- Institute for Solid State Physics, University of Tokyo, Kashiwa, Chiba 277-8581, Japan
- CREST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012, Japan
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13
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Little A, Wu L, Lampen-Kelley P, Banerjee A, Patankar S, Rees D, Bridges CA, Yan JQ, Mandrus D, Nagler SE, Orenstein J. Antiferromagnetic Resonance and Terahertz Continuum in α-RuCl_{3}. Phys Rev Lett 2017; 119:227201. [PMID: 29286790 DOI: 10.1103/physrevlett.119.227201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Indexed: 06/07/2023]
Abstract
We report measurements of optical absorption in the zigzag antiferromagnet α-RuCl_{3} as a function of temperature T, magnetic field B, and photon energy ℏω in the range ∼0.3-8.3 meV, using time-domain terahertz spectroscopy. Polarized measurements show that threefold rotational symmetry is broken in the honeycomb plane from 2 to 300 K. We find a sharp absorption peak at 2.56 meV upon cooling below the Néel temperature of 7 K at B=0 that we identify as the magnetic-dipole excitation of a zero-wave-vector magnon, or antiferromagnetic resonance (AFMR). With the application of B, the AFMR broadens and shifts to a lower frequency as long-range magnetic order is lost in a manner consistent with transitioning to a spin-disordered phase. From a direct, internally calibrated measurement of the AFMR spectral weight, we place an upper bound on the contribution to the dc susceptibility from a magnetic excitation continuum.
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Affiliation(s)
- A Little
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Liang Wu
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
- Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - P Lampen-Kelley
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - A Banerjee
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - S Patankar
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - D Rees
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - C A Bridges
- Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
| | - J-Q Yan
- Material Sciences and Technology Division, Oak Ridge National Laboratory, Oak Ridge,Tennessee 37830, USA
| | - D Mandrus
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, USA
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - S E Nagler
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
- Bredesen Center, University of Tennessee, Knoxville, Tennessee 37966, USA
| | - J Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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14
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Abstract
Several emergent phenomena and phases in solids arise from configurations of the electronic Berry phase in momentum space that are similar to gauge field configurations in real space such as magnetic monopoles. We show that the momentum-space analogue of the "axion electrodynamics" term E·B plays a fundamental role in a unified theory of Berry-phase contributions to optical gyrotropy in time-reversal invariant materials and the chiral magnetic effect. The Berry-phase mechanism predicts that the rotatory power along the optic axes of a crystal must sum to zero, a constraint beyond that stipulated by point-group symmetry, but observed to high accuracy in classic experimental observations on alpha quartz. Furthermore, the Berry mechanism provides a microscopic basis for the surface conductance at the interface between gyrotropic and nongyrotropic media.
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Affiliation(s)
- Shudan Zhong
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Joseph Orenstein
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Joel E Moore
- Department of Physics, University of California, Berkeley, California 94720, USA and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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15
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Hinton JP, Koralek JD, Yu G, Motoyama EM, Lu YM, Vishwanath A, Greven M, Orenstein J. Time-resolved optical reflectivity of the electron-doped Nd(2-x)Ce(x)CuO(4+δ) cuprate superconductor: evidence for an interplay between competing orders. Phys Rev Lett 2013; 110:217002. [PMID: 23745913 DOI: 10.1103/physrevlett.110.217002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2012] [Revised: 02/08/2013] [Indexed: 06/02/2023]
Abstract
We use pump-probe spectroscopy to measure the photoinduced reflectivity ΔR of the electron-doped cuprate superconductor Nd(2-x)Ce(x)CuO(4+δ) at a value of x near optimal doping, as a function of time, temperature, and laser fluence. We observe the onset of a negative ΔR signal at T(*)≈75 K, above the superconducting transition temperature, T(c), of 23 K. The relatively slow decay of ΔR, compared to the analogous signal in hole doped compounds, allows us to resolve time-temperature scaling consistent with critical fluctuations. A positive ΔR signal onsets at T(c) that we associate with superconducting order. We find that the two signals are strongly coupled below T(c), in a manner that suggests a repulsive interaction between superconductivity and another fluctuating order.
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Affiliation(s)
- J P Hinton
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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16
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Koralek JD, Yang L, Tibbetts DR, Reno JL, Lilly MP, Orenstein J. Doppler velocimetry of spin and charge currents in the 2D Fermi gas. EPJ Web of Conferences 2013. [DOI: 10.1051/epjconf/20134103017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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17
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Koralek JD, Meier D, Hinton JP, Bauer A, Parameswaran SA, Vishwanath A, Ramesh R, Schoenlein RW, Pfleiderer C, Orenstein J. Observation of coherent helimagnons and gilbert damping in an itinerant magnet. Phys Rev Lett 2012; 109:247204. [PMID: 23368372 DOI: 10.1103/physrevlett.109.247204] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Indexed: 06/01/2023]
Abstract
We study the magnetic excitations of itinerant helimagnets by applying time-resolved optical spectroscopy to Fe(0.8)Co(0.2)Si. Optically excited oscillations of the magnetization in the helical state are found to disperse to lower frequency as the applied magnetic field is increased; the fingerprint of collective modes unique to helimagnets, known as helimagnons. The use of time-resolved spectroscopy allows us to address the fundamental magnetic relaxation processes by directly measuring the Gilbert damping, revealing the versatility of spin dynamics in chiral magnets.
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Affiliation(s)
- J D Koralek
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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18
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Yang L, Koralek JD, Orenstein J, Tibbetts DR, Reno JL, Lilly MP. Coherent propagation of spin helices in a quantum-well confined electron gas. Phys Rev Lett 2012; 109:246603. [PMID: 23368357 DOI: 10.1103/physrevlett.109.246603] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Indexed: 06/01/2023]
Abstract
We use phase-resolved transient grating spectroscopy to measure the propagation of spin helices in a high mobility n-GaAs/AlGaAs quantum well with an applied in-plane electric field. At relatively low fields helical modes crossover from overdamped excitations where the spin-precession period exceeds the spin lifetime, to a regime of coherent propagation where several spin-precession periods can be observed. We demonstrate that the envelope of a spin polarization packet reaches a current-driven velocity of 10(7) cm s(-1) in an applied field of 70 V cm(-1).
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Affiliation(s)
- Luyi Yang
- Department of Physics, University of California, Berkeley, California 94720, USA
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19
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Smallwood CL, Hinton JP, Jozwiak C, Zhang W, Koralek JD, Eisaki H, Lee DH, Orenstein J, Lanzara A. Tracking Cooper Pairs in a Cuprate Superconductor by Ultrafast Angle-Resolved Photoemission. Science 2012; 336:1137-9. [DOI: 10.1126/science.1217423] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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20
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Abstract
Rotation of the plane of polarization of reflected light (Kerr effect) is a direct manifestation of broken time-reversal symmetry and is generally associated with the appearance of a ferromagnetic moment. Here I identify magnetic structures that may arise within the unit cell of cuprate superconductors that generate polarization rotation despite the absence of a net moment. For these magnetic symmetries the Kerr effect is mediated by magnetoelectric coupling, which can arise when antiferromagnetic order breaks inversion symmetry. The structures identified are candidates for a time-reversal breaking phase in the pseudogap regime of the cuprates.
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Affiliation(s)
- J Orenstein
- Department of Physics, University of California, Berkeley, 94720, USA
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21
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Yang L, Koralek JD, Orenstein J, Tibbetts DR, Reno JL, Lilly MP. Measurement of electron-hole friction in an n-doped GaAs/AlGaAs quantum well using optical transient grating spectroscopy. Phys Rev Lett 2011; 106:247401. [PMID: 21770596 DOI: 10.1103/physrevlett.106.247401] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Indexed: 05/31/2023]
Abstract
We use phase-resolved transient grating spectroscopy to measure the drift and diffusion of electron-hole density waves in a semiconductor quantum well. The unique aspects of this optical probe allow us to determine the frictional force between a two-dimensional Fermi liquid of electrons and a dilute gas of holes. Knowledge of electron-hole friction enables prediction of ambipolar dynamics in high-mobility electron systems.
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Affiliation(s)
- Luyi Yang
- Department of Physics, University of California, Berkeley, California 94720, USA
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22
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He RH, Hashimoto M, Karapetyan H, Koralek JD, Hinton JP, Testaud JP, Nathan V, Yoshida Y, Yao H, Tanaka K, Meevasana W, Moore RG, Lu DH, Mo SK, Ishikado M, Eisaki H, Hussain Z, Devereaux TP, Kivelson SA, Orenstein J, Kapitulnik A, Shen ZX. From a single-band metal to a high-temperature superconductor via two thermal phase transitions. Science 2011; 331:1579-83. [PMID: 21436447 DOI: 10.1126/science.1198415] [Citation(s) in RCA: 270] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The nature of the pseudogap phase of cuprate high-temperature superconductors is a major unsolved problem in condensed matter physics. We studied the commencement of the pseudogap state at temperature T* using three different techniques (angle-resolved photoemission spectroscopy, polar Kerr effect, and time-resolved reflectivity) on the same optimally doped Bi2201 crystals. We observed the coincident, abrupt onset at T* of a particle-hole asymmetric antinodal gap in the electronic spectrum, a Kerr rotation in the reflected light polarization, and a change in the ultrafast relaxational dynamics, consistent with a phase transition. Upon further cooling, spectroscopic signatures of superconductivity begin to grow close to the superconducting transition temperature (T(c)), entangled in an energy-momentum-dependent manner with the preexisting pseudogap features, ushering in a ground state with coexisting orders.
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Affiliation(s)
- Rui-Hua He
- Geballe Laboratory for Advanced Materials, Departments of Physics and Applied Physics, Stanford University, Stanford, CA 94305, USA
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23
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Abstract
ABSTRACTWe present femtosecond time-resolved transient absorption data taken on polydiacetylene-pTS single crystals over the entire wavelength region of exciton resonance. Observed optical changes are accounted for by a model which predicts quantitatively the large resonant and nonresonant optical nonlinearities.
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24
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Abstract
The photocurrent in an optically active metal is known to contain a component that switches sign with the helicity of the incident radiation. At low frequencies, this current depends on the orbital Berry phase of the Bloch electrons via the "anomalous velocity" of Karplus and Luttinger. We consider quantum wells in which the parent material, such as GaAs, is not optically active and the relevant Berry phase only arises as a result of quantum confinement. Using an envelope approximation that is supported by numerical tight-binding results, it is shown that the Berry-phase contribution is determined for realistic wells by a cubic Berry phase intrinsic to the bulk material, the well width, and the well direction. These results for the Berry-phase effect suggest that it may already have been observed in quantum well experiments.
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Affiliation(s)
- J E Moore
- Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA
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25
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Koralek JD, Weber CP, Orenstein J, Bernevig BA, Zhang SC, Mack S, Awschalom DD. Emergence of the persistent spin helix in semiconductor quantum wells. Nature 2009; 458:610-3. [PMID: 19340077 DOI: 10.1038/nature07871] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2008] [Accepted: 01/30/2009] [Indexed: 11/09/2022]
Abstract
According to Noether's theorem, for every symmetry in nature there is a corresponding conservation law. For example, invariance with respect to spatial translation corresponds to conservation of momentum. In another well-known example, invariance with respect to rotation of the electron's spin, or SU(2) symmetry, leads to conservation of spin polarization. For electrons in a solid, this symmetry is ordinarily broken by spin-orbit coupling, allowing spin angular momentum to flow to orbital angular momentum. However, it has recently been predicted that SU(2) can be achieved in a two-dimensional electron gas, despite the presence of spin-orbit coupling. The corresponding conserved quantities include the amplitude and phase of a helical spin density wave termed the 'persistent spin helix'. SU(2) is realized, in principle, when the strengths of two dominant spin-orbit interactions, the Rashba (strength parameterized by alpha) and linear Dresselhaus (beta(1)) interactions, are equal. This symmetry is predicted to be robust against all forms of spin-independent scattering, including electron-electron interactions, but is broken by the cubic Dresselhaus term (beta(3)) and spin-dependent scattering. When these terms are negligible, the distance over which spin information can propagate is predicted to diverge as alpha approaches beta(1). Here we report experimental observation of the emergence of the persistent spin helix in GaAs quantum wells by independently tuning alpha and beta(1). Using transient spin-grating spectroscopy, we find a spin-lifetime enhancement of two orders of magnitude near the symmetry point. Excellent quantitative agreement with theory across a wide range of sample parameters allows us to obtain an absolute measure of all relevant spin-orbit terms, identifying beta(3) as the main SU(2)-violating term in our samples. The tunable suppression of spin relaxation demonstrated in this work is well suited for application to spintronics.
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Affiliation(s)
- J D Koralek
- Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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26
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Langner MC, Kantner CLS, Chu YH, Martin LM, Yu P, Seidel J, Ramesh R, Orenstein J. Observation of ferromagnetic resonance in SrRuO3 by the time-resolved magneto-optical Kerr effect. Phys Rev Lett 2009; 102:177601. [PMID: 19518833 DOI: 10.1103/physrevlett.102.177601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Indexed: 05/27/2023]
Abstract
We report the observation of ferromagnetic resonance (FMR) in SrRuO3 using the time-resolved magneto-optical Kerr effect. The FMR oscillations in the time-domain appear in response to a sudden, optically induced change in the direction of easy-axis anisotropy. The high FMR frequency, 250 GHz, and large Gilbert damping parameter, alpha approximately 1, are consistent with strong spin-orbit coupling. We find that the parameters associated with the magnetization dynamics, including alpha, have a nonmonotonic temperature dependence, suggestive of a link to the anomalous Hall effect.
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Affiliation(s)
- M C Langner
- Department of Physics, University of California, Berkeley, California 94720, USA
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27
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Seidel J, Martin LW, He Q, Zhan Q, Chu YH, Rother A, Hawkridge ME, Maksymovych P, Yu P, Gajek M, Balke N, Kalinin SV, Gemming S, Wang F, Catalan G, Scott JF, Spaldin NA, Orenstein J, Ramesh R. Conduction at domain walls in oxide multiferroics. Nat Mater 2009; 8:229-34. [PMID: 19169247 DOI: 10.1038/nmat2373] [Citation(s) in RCA: 392] [Impact Index Per Article: 26.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2008] [Accepted: 12/22/2008] [Indexed: 05/14/2023]
Abstract
Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO(3). The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.
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Affiliation(s)
- J Seidel
- Department of Physics, University of California, Berkeley, 94720 California, USA.
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28
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Kajdacsy-Balla A, Geynisman JM, Macias V, Setty S, Nanaji NM, Berman JJ, Dobbin K, Melamed J, Kong X, Bosland M, Orenstein J, Bayerl J, Becich MJ, Dhir R, Datta MW. Practical aspects of planning, building, and interpreting tissue microarrays: The Cooperative Prostate Cancer Tissue Resource experience. J Mol Histol 2007; 38:113-21. [PMID: 17318343 DOI: 10.1007/s10735-006-9054-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2006] [Accepted: 08/23/2006] [Indexed: 10/23/2022]
Abstract
This is a review of several new approaches developed at or adopted by the Cooperative Prostate Cancer Tissue Resource (CPCTR) to resolve issues involved in tissue microarray (TMA) construction and use. CPCTR developed the first needle biopsy TMA, allowing researchers to obtain 200 or more consecutive cancer sections from a single biopsy core. Using radiographs of original paraffin blocks to measure tissue thickness we developed a method to produce TMAs with a larger number of usable sections. The modular approach to plan TMA construction is also a novel concept wherein TMAs of different types, such as tumor grade TMAs, metastasis TMA and hormone refractory tumors TMA can be combined to form an ensemble of TMAs with expanded research utility, such as support for tumor progression studies. We also implemented an open access TMA Data Exchange Specification that allows TMA data to be organized in a self-describing XML document annotated with well-defined common data elements. It ensures inter-laboratory reproducibility because it offers information describing the preparation of TMA blocks and slides. There are many important aspects that may be missed by both beginners and experienced investigators in areas of TMA experimental design, human subjects protection, population sample size, selection of tumor areas to sample, strategies for saving tissues, choice of antibodies for immunohistochemistry, and TMA data management.
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Affiliation(s)
- A Kajdacsy-Balla
- Department of Pathology, University of Illinois Chicago, Chicago, IL 60607-7053, USA.
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29
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Weber CP, Orenstein J, Bernevig BA, Zhang SC, Stephens J, Awschalom DD. Nondiffusive spin dynamics in a two-dimensional electron gas. Phys Rev Lett 2007; 98:076604. [PMID: 17359043 DOI: 10.1103/physrevlett.98.076604] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2006] [Indexed: 05/14/2023]
Abstract
We describe measurements of spin dynamics in the two-dimensional electron gas in GaAs/GaAlAs quantum wells. Optical techniques, including transient spin-grating spectroscopy, are used to probe the relaxation rates of spin polarization waves in the wave vector range from zero to 6x10(4) cm-1. We find that the spin polarization lifetime is maximal at a nonzero wave vector, in contrast with expectations based on ordinary spin diffusion, but in quantitative agreement with recent theories that treat diffusion in the presence of spin-orbit coupling.
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Affiliation(s)
- C P Weber
- Physics Department, University of California, Berkeley and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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30
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Bernevig BA, Orenstein J, Zhang SC. Exact SU(2) symmetry and persistent spin helix in a spin-orbit coupled system. Phys Rev Lett 2006; 97:236601. [PMID: 17280220 DOI: 10.1103/physrevlett.97.236601] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Indexed: 05/13/2023]
Abstract
Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constants, and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions and is generated by operators whose wave vector depends on the coupling strength. It renders the spin lifetime infinite at this wave vector, giving rise to a persistent spin helix. We obtain the spin fluctuation dynamics at, and away from, the symmetry point and suggest experiments to observe the persistent spin helix.
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Affiliation(s)
- B Andrei Bernevig
- Department of Physics, McCullough Building, Stanford University, Stanford, California 94305-4045, USA
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Affiliation(s)
| | - M. A. Kastner
- a Department of Physics and Center for Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , U.S.A
| | - V. Vaninov
- c Hewlett Packard, Andover Div. , 1776 Minuteman Road, Andover , Massachusetts , 01810 , U.S.A
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Affiliation(s)
- V. Vaninov
- b Hewlett Packard, Andover Division , 1776 Minuteman Road, Andover , Massachusetts , 01810 , U.S.A
| | - J. Orenstein
- c Bell Laboratories , Murray Hill , New Jersey , 07974 , U.S.A
| | - M. A. Kastner
- a Department of Physics and Center for Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts , 02139 , U.S.A
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Weber CP, Gedik N, Moore JE, Orenstein J, Stephens J, Awschalom DD. Observation of spin Coulomb drag in a two-dimensional electron gas. Nature 2005; 437:1330-3. [PMID: 16251958 DOI: 10.1038/nature04206] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Accepted: 09/02/2005] [Indexed: 11/08/2022]
Abstract
An electron propagating through a solid carries spin angular momentum in addition to its mass and charge. Of late there has been considerable interest in developing electronic devices based on the transport of spin that offer potential advantages in dissipation, size and speed over charge-based devices. However, these advantages bring with them additional complexity. Because each electron carries a single, fixed value (- e) of charge, the electrical current carried by a gas of electrons is simply proportional to its total momentum. A fundamental consequence is that the charge current is not affected by interactions that conserve total momentum, notably collisions among the electrons themselves. In contrast, the electron's spin along a given spatial direction can take on two values, +/- [planck]/2 (conventionally upward arrow, downward arrow), so that the spin current and momentum need not be proportional. Although the transport of spin polarization is not protected by momentum conservation, it has been widely assumed that, like the charge current, spin current is unaffected by electron-electron (e-e) interactions. Here we demonstrate experimentally not only that this assumption is invalid, but also that over a broad range of temperature and electron density, the flow of spin polarization in a two-dimensional gas of electrons is controlled by the rate of e-e collisions.
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Affiliation(s)
- C P Weber
- Physics Department, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
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34
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Gedik N, Langner M, Langer M, Orenstein J, Ono S, Abe Y, Ando Y. Abrupt transition in quasiparticle dynamics at optimal doping in a cuprate superconductor system. Phys Rev Lett 2005; 95:117005. [PMID: 16197037 DOI: 10.1103/physrevlett.95.117005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Indexed: 05/04/2023]
Abstract
We report time-resolved measurements of the photoinduced change in reflectivity, DeltaR, in the Bi2Sr2Ca(1-y)Dy(y)Cu2O8+delta (BSCCO) system of cuprate superconductors as a function of hole concentration. We find that the kinetics of quasiparticle decay and the sign of DeltaR both change abruptly where the superconducting transition temperature T(c) is maximal. These coincident changes suggest that a sharp transition in quasiparticle dynamics takes place precisely at optimal doping in the BSCCO system.
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Affiliation(s)
- N Gedik
- Physics Department, University of California, Berkeley, Berkeley, California, USA
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Abstract
We present a method of measuring the absolute phase in heterodyne-detected transient grating experiments. The method permits direct and sensitive characterization of the amplitude and phase of the grating parameters. We also present a convenient implementation of this technique and demonstrate its efficacy in a cuprate superconductor.
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Affiliation(s)
- Nuh Gedik
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Department of Physics, University of California, Berkeley, Berkeley, California 94720, USA.
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36
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Abstract
We report a transport study of nonequilibrium quasi-particles in a high-transition-temperature cuprate superconductor using the transient grating technique. Low-intensity laser excitation (at a photon energy of 1.5 electron volts) was used to introduce a spatially periodic density of quasi-particles into a high-quality untwinned single crystal of YBa2Cu3O6.5. Probing the evolution of the initial density through space and time yielded the quasi-particle diffusion coefficient and the inelastic and elastic scattering rates. The technique reported here is potentially applicable to precision measurements of quasi-particle dynamics not only in cuprate superconductors but in other electronic systems as well.
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Affiliation(s)
- N Gedik
- Physics Department, University of California, Berkeley, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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37
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McElroy K, Simmonds RW, Hoffman JE, Lee DH, Orenstein J, Eisaki H, Uchida S, Davis JC. Relating atomic-scale electronic phenomena to wave-like quasiparticle states in superconducting Bi2Sr2CaCu2O8+delta. Nature 2003; 422:592-6. [PMID: 12686994 DOI: 10.1038/nature01496] [Citation(s) in RCA: 398] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2002] [Accepted: 02/14/2003] [Indexed: 11/09/2022]
Abstract
The electronic structure of simple crystalline solids can be completely described in terms either of local quantum states in real space (r-space), or of wave-like states defined in momentum-space (k-space). However, in the copper oxide superconductors, neither of these descriptions alone may be sufficient. Indeed, comparisons between r-space and k-space studies of Bi2Sr2CaCu2O8+delta (Bi-2212) reveal numerous unexplained phenomena and apparent contradictions. Here, to explore these issues, we report Fourier transform studies of atomic-scale spatial modulations in the Bi-2212 density of states. When analysed as arising from quasiparticle interference, the modulations yield elements of the Fermi-surface and energy gap in agreement with photoemission experiments. The consistency of numerous sets of dispersing modulations with the quasiparticle interference model shows that no additional order parameter is required. We also explore the momentum-space structure of the unoccupied states that are inaccessible to photoemission, and find strong similarities to the structure of the occupied states. The copper oxide quasiparticles therefore apparently exhibit particle-hole mixing similar to that of conventional superconductors. Near the energy gap maximum, the modulations become intense, commensurate with the crystal, and bounded by nanometre-scale domains. Scattering of the antinodal quasiparticles is therefore strongly influenced by nanometre-scale disorder.
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Affiliation(s)
- K McElroy
- Department of Physics, University of California, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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38
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Segre GP, Gedik N, Orenstein J, Bonn DA, Liang R, Hardy WN. Photoinduced changes of reflectivity in single crystals of YBa2Cu3O6.5 (ortho II). Phys Rev Lett 2002; 88:137001. [PMID: 11955115 DOI: 10.1103/physrevlett.88.137001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2001] [Indexed: 05/23/2023]
Abstract
We report measurements of the photoinduced change in reflectivity of an untwinned single crystal of YBa2Cu3O6.5 in the ortho II structure. The decay rate of the transient change in reflectivity is found to decrease rapidly with decreasing temperature and, below T(c), with decreasing laser intensity. We interpret the decay as a process of thermalization of antinodal quasiparticles, with a rate determined by inelastic scattering of quasiparticle pairs.
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Affiliation(s)
- G P Segre
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Physics Department, University of California, Berkeley, California 94720, USA
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Kaindl RA, Carnahan MA, Orenstein J, Chemla DS, Christen HM, Zhai HY, Paranthaman M, Lowndes DH. Far-infrared optical conductivity gap in superconducting MgB2 films. Phys Rev Lett 2002; 88:027003. [PMID: 11801029 DOI: 10.1103/physrevlett.88.027003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2001] [Indexed: 05/23/2023]
Abstract
We report the first study of the optical conductivity of MgB2 covering the range of its lowest-energy superconducting gap. Terahertz time-domain spectroscopy is utilized to determine the complex, frequency-dependent conductivity sigma(omega) of thin films. The imaginary part reveals an inductive response due to the emergence of the superconducting condensate. The real part exhibits a strong depletion of oscillator strength near 5 meV resulting from the opening of a superconducting energy gap. The gap ratio of 2Delta0/k(B)TC approximately 1.9 is well below the weak-coupling value, pointing to complex behavior in this novel superconductor.
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Affiliation(s)
- Robert A Kaindl
- Department of Physics, University of California at Berkeley, and Materials Sciences Division, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Smith SM, Khoroshev M, Marx PA, Orenstein J, Jeang KT. Constitutively dead, conditionally live HIV-1 genomes. Ex vivo implications for a live virus vaccine. J Biol Chem 2001; 276:32184-90. [PMID: 11397795 DOI: 10.1074/jbc.m101604200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An effective vaccine against AIDS is unlikely to be available for many years. As we approach two decades since the first identification of human immunodeficiency virus, type 1 (HIV-1), currently, only one subunit vaccine candidate has reached phase 3 of clinical trials. The subunit approach has been criticized for its inability to elicit effectively cytotoxic T-lymphocyte (CTL) response, which is felt by many to be needed for protection against HIV-1 infection. In subhuman primates, a live attenuated simian immunodeficiency virus (SIV) vaccine candidate, capable of inducing CTL, has been found to confer prophylactic immunity sufficient to prevent simian AIDS. Because replication competent (live) attenuated viruses could over time revert to virulence, such a live attenuated approach has largely been dismissed for HIV-1. Here, we describe the creation of constitutively dead conditionally live (CDCL) HIV-1 genomes. These genomes are constitutively defective for the Tat/TAR axis and are conditionally dependent on tetracycline for attenuated replication with robust expression of viral antigens. Our results suggest that CDCL genomes merit consideration as safer "live" attenuated HIV-1 vaccine candidates.
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Affiliation(s)
- S M Smith
- Saint Michael's Medical Center and the New Jersey Medical School-University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07102, USA
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41
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Dodge JS, Weber CP, Corson J, Orenstein J, Schlesinger Z, Reiner JW, Beasley MR. Low-frequency crossover of the fractional power-Law conductivity in SrRuO3. Phys Rev Lett 2000; 85:4932-4935. [PMID: 11102154 DOI: 10.1103/physrevlett.85.4932] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2000] [Indexed: 05/23/2023]
Abstract
We combine the results of terahertz time-domain spectroscopy with far-infrared transmission and reflectivity to obtain the conductivity of SrRuO3 over an unprecedented continuous range in frequency, allowing us to characterize the approach to zero frequency as a function of temperature. We show that the conductivity follows a simple phenomenological form, with an analytic structure fundamentally different from that predicted by the standard theory of metals.
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Affiliation(s)
- JS Dodge
- Department of Physics, University of California at Berkeley, Berkeley, California 94720 and Materials Sciences Division, E. O. Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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Corson J, Orenstein J, Oh S, O'Donnell J, Eckstein JN. Nodal quasiparticle lifetime in the superconducting state of Bi(2)Sr(2)CaCu(2)O(8+delta). Phys Rev Lett 2000; 85:2569-2572. [PMID: 10978109 DOI: 10.1103/physrevlett.85.2569] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2000] [Indexed: 05/23/2023]
Abstract
We have measured the complex conductivity sigma of a Bi(2)Sr(2)CaCu(2)O(8+delta) thin film between 0.2 and 0.8 THz. We find sigma in the superconducting state to be well described as the sum of contributions from quasiparticles, condensate, and order parameter fluctuations which draw 30% of the spectral weight from the condensate. An analysis based on this decomposition yields a quasiparticle scattering rate on the order of k(B)T/Planck's over 2pi for temperatures below T(c).
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Affiliation(s)
- J Corson
- Materials Sciences Division, Lawrence Berkeley National Laboratory and Physics Department, University of California, Berkeley, California 94720, USA
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Abstract
This study was concerned with the effects of NaCl administered in vivo or added in vitro to isolated nuclei on [(3)H]tryptophan binding to rat hepatic nuclei assayed in vitro. Hypertonic (10.7%) NaCl administered in vivo to rats caused at 10 min a marked decrease in in vitro binding (total and specific) of [(3)H]tryptophan to hepatic nuclei. In vitro incubation of isolated hepatic nuclei, but not of isolated nuclear envelopes, with added NaCl (particularly at 0.125 x 10(-4) M and 0.25 x 10(-4) M) revealed significant inhibition of [(3)H]tryptophan binding. However, isolated hepatic nuclear envelopes prepared after in vitro incubation of isolated nuclei with added NaCl did show inhibition of [(3)H]tryptophan binding (total and specific) compared with controls. Other salts (KCl, MgCl(2), NaHCO(3), NaC(2)H(3)O(2), NaF, or Na(2)SO(4)), at similar concentrations to that of NaCl except for MgCl(2), when added to isolated nuclei did not appreciably inhibit nuclear tryptophan binding. Kinetic studies of in vitro nuclear [(3)H]tryptophan binding in the presence of 0.125 x 10(-4) M NaCl revealed that binding decreased at 0.5 h and continued to 2 h compared with nuclear [(3)H]tryptophan binding with controls (without NaCl addition). The results obtained in vivo in rats and those obtained in vitro with isolated hepatic nuclei revealed NaCl-induced inhibitory effects on [(3)H]tryptophan binding to hepatic nuclei. Although the inhibitory effects were similar under the two different experimental conditions, the mechanism for each may be different in that the NaCl concentration in hepatic cells after administration of NaCl in vivo was appreciably higher than the low levels added in vitro to the isolated hepatic nuclei.
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Affiliation(s)
- H Sidransky
- Department of Pathology, George Washington University Medical Center, Washington, DC 20037, USA
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Zhang H, Dornadula G, Orenstein J, Pomerantz RJ. Morphologic changes in human immunodeficiency virus type 1 virions secondary to intravirion reverse transcription: evidence indicating that reverse transcription may not take place within the intact viral core. J Hum Virol 2000; 3:165-72. [PMID: 10881997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
INTRODUCTION In the past, retroviral endogenous reverse transcription (ERT) was considered an artificial process, secondary to permeabilization of the viral envelope by detergents or amphipathic peptides. However, recently we have demonstrated that ERT may occur in a variety of lentiviruses without detergent treatment and may lead to increased infectivity of lentivirions in initially quiescent T lymphocytes and nonproliferating cells, such as macrophages. As full-length reverse transcripts could be synthesized within lentiviral particles, it is worth evaluating the potential alterations in lentiviral morphology due to the stimulation of intravirion reverse transcription. METHODS Using quantitative DNA-polymerase chain reaction (PCR) and transmission electron microscopy (TEM), we characterized critical alterations in human immunodeficiency virus type 1 (HIV-1) virions after stimulation of intravirion reverse transcription. RESULTS Intravirion reverse transcription in HIV-1 virions was stimulated using deoxyribonucleoside triphosphates (dNTPs) and physiologic polyamines. Our studies indicated that HIV-1 virions, in which intravirion reverse transcription was stimulated, showed dissolution of the p24-shelled viral core and absence of the core-envelope linkage (CEL) region by TEM. These changes in the structure of the core correlate with the in vitro alterations in virion infectivity on primary cells. CONCLUSIONS Stimulation of intravirion HIV-1 reverse transcription leads to morphologic changes in the viral particles that suggest changes in the compact viral core, which is consistent with active reverse transcription before infection of target cells. Further, via this unique approach, we suggest that intravirion or intracellular reverse transcription of HIV-1 is unlikely to take place within intact viral cores made up of p24-containing outer shells. As such, these results suggest a new approach to further dissect the intravirion or intracellular reverse transcription machinery of lentiviruses.
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Affiliation(s)
- H Zhang
- The Dorrance H. Hamilton Laboratories, Center for Human Virology, Department of Medicine, Jefferson Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA
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Abstract
The high-temperature copper oxide superconductors are of fundamental and enduring interest. They not only manifest superconducting transition temperatures inconceivable 15 years ago, but also exhibit many other properties apparently incompatible with conventional metal physics. The materials expand our notions of what is possible, and compel us to develop new experimental techniques and theoretical concepts. This article provides a perspective on recent developments and their implications for our understanding of interacting electrons in metals.
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Affiliation(s)
- J Orenstein
- Department of Physics, University of California, Berkeley, CA 94720, USA, and Materials Science Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA. Department of Physics and Astronomy, Rutgers University, Piscataway, NJ
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Lynn J, Cobbs E, Orenstein J. Autopsy rates and diagnosis. JAMA 1999; 281:2181; author reply 2184-5. [PMID: 10376558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Kolesnitchenko V, Wahl LM, Tian H, Sunila I, Tani Y, Hartmann DP, Cossman J, Raffeld M, Orenstein J, Samelson LE, Cohen DI. Human immunodeficiency virus 1 envelope-initiated G2-phase programmed cell death. Proc Natl Acad Sci U S A 1995; 92:11889-93. [PMID: 8524869 PMCID: PMC40508 DOI: 10.1073/pnas.92.25.11889] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Despite intensive investigation, no clearly defined mechanism explaining human immunodeficiency virus (HIV)-induced cell killing has emerged. HIV-1 infection is initiated through a high-affinity interaction between the HIV-1 external envelope glycoprotein (gp120) and the CD4 receptor on T cells. Cell killing is a later event intimately linked by in vitro genetic analyses with the fusogenic properties of the HIV envelope glycoprotein gp120 and transmembrane glycoprotein gp41. In this report, we describe aberrancies in cell cycle regulatory proteins initiated by cell-cell contact between T cells expressing HIV-1 envelope glycoproteins and other T cells expressing CD4 receptors. Cells rapidly accumulate cyclin B protein and tyrosine-hyperphosphorylated p34cdc2 (cdk1) kinase, indicative of cell cycle arrest at G2 phase. Moreover, these cells continue to synthesize cyclin B protein, enlarge and display an abnormal ballooned morphology, and disappear from the cultures in a pattern previously described for cytotoxicity induced by DNA synthesis (S phase) inhibitors. Similar changes are observed in peripheral blood mononuclear cells infected in vitro with pathogenic primary isolates of HIV-1.
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Affiliation(s)
- V Kolesnitchenko
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Maldarelli F, Sato H, Berthold E, Orenstein J, Martin MA. Rapid induction of apoptosis by cell-to-cell transmission of human immunodeficiency virus type 1. J Virol 1995; 69:6457-65. [PMID: 7666547 PMCID: PMC189546 DOI: 10.1128/jvi.69.10.6457-6465.1995] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The kinetics of human immunodeficiency virus type 1 (HIV-1)-induced cell death were investigated in cell-to-cell and cell-free models of virus transmission. Cocultivation of HIV-1 chronically infected H9 donor cells with uninfected H9 recipient cells resulted in rapid induction of programmed cell death. Within 8 h, apoptotic chromatin condensation was identified by histologic staining. In addition, many single cells with apoptotic nuclei were observed, indicating that stable cell fusion was not a requirement for apoptosis to occur. By 12 to 18 h of coculture, a DNA fragmentation ladder characteristic of apoptosis was detected by agarose gel electrophoresis. Quantitation of apoptosis by measurement of nuclear DNA content revealed that at least 20 to 30% of the nuclei were undergoing apoptosis by 24 h after cocultivation. The appearance of condensed nuclei and fragmented DNA occurred as HIV reverse transcription was completed, and it was not inhibited by zidovudine, suggesting that induction of apoptosis did not require new HIV replication. Soluble CD4 inhibited apoptosis, demonstrating that Env-CD4 interactions were required for apoptosis. In contrast to that in cell-to-cell transmission, apoptosis in cell-free HIV infections was markedly inefficient and was not observed until 70 to 90 h after infections were initiated. These findings indicate that HIV-1 induction of programmed destruction of the nucleus is initiated at the time of cell-cell cocultivation by a mechanism which requires CD4-Env interactions but not new HIV replication.
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Affiliation(s)
- F Maldarelli
- Laboratory of Molecular Microbiology, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892, USA
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