Spring Meeting 2017 in Dresden

2001 - 2002 - 2003 - 2004 - 2005 - 2006 - 2007 - 2008 - 2009 - 2010 - 2011 - 2012 - 2013 - 2014 - 2015 - 2016 - 2017

Deutsche Physikalische Gesellschaft e. V. (DPG)

TT 4: Transport: Topological Insulators (jointly with DS, MA, HL, O)

TT 4.1: Vortrag, Montag, 20. März 2017, 09:30–09:45, HSZ 204

Magnetic excitations in the symmetry protected, topological Haldane phase of SrNi2V2O8Vladimir Gnezdilov1,2, Vladimir Kurnosov2, •Peter Lemmens1, A. K. Bera3, A. T. M. N. Islam3, and Bella Lake31TU-BS, Braunschweig — 2ILTP Kharkov — 3HZB Berlin

We report results of a single-crystal Raman scattering study of the coupled spin-1 Haldane chain compound SrNi2V2O8. In addition to the one-and two-magnon excitations, broad gapless and temperature dependent continua are detected with light polarization parallel to the basal plane. This feature is discussed in terms of spinon-like excitations related to a symmetry protected topological state, of which the Haldane phase in 1D is a preeminent example. Work supported by RTG-DFG 1952/1, Metrology for Complex Nanosystems and the Laboratory for Emerging Nanometrology, TU Braunschweig.

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TT 42: Correlated Electrons: Frustrated Magnets - Strong Spin-Orbit Coupling 2

TT 42.4: Vortrag, Mittwoch, 22. März 2017, 10:15–10:30, HSZ 304

Spectroscopic investigations of a novel Iridate - a possible reference material for Kitaev physicsPhilipp Benrath1, Angela Möller1, Vladimir Gnezdilov2,3, and •Peter Lemmens21IAC-AC, JGU Mainz — 2TU-BS, Braunschweig — 3ILTP, Kharvov

In Na2Ir(OH)6 there exist a D3d point group symmetry with an uniaxial threefold symmetry of the iridium complex. In our search for nonabelian anyons (fractionalized excitations)[1] we performed a systematic Raman scattering investigation of its excitation spectrum. Evidence for a symmetry reduction and its relation to other distorted Kitaev materials are discussed. Work supported by RTG-DFG 1952/1, the Laboratory for Emerging Nanometrology, TU Braunschweig, and NTH Contacs in Nanosystems.

[1] A. Glamazda, P. Lemmens, S.-H. Do, K.-Y. Choi, Nature Commun. 7, 12286 (2016).

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TT 42.11: Vortrag, Mittwoch, 22. März 2017, 12:15–12:30, HSZ 304

Effect of symmetry and local distortions on fractionalized excitations in Kitaev Systems — •Peter Lemmens1, Vladimir Gnezdilov1,2, Alexander Glamazda1,2,3, S.-H. Do3, K.-Y. Choi3, Angela Möller4, Friedrich Freund5, and Philipp Gegenwart51TU-BS Braunschweig — 2ILTP Kharkov — 3CAU Seoul — 4IAC-AC, JGU Mainz — 5EP-VI, ZEKM, Augsburg

In Kitaev physics the role of symmetry is crucial. A prerequisite of the Kitaev model demands uniaxial threefold symmetry of the iridium complex. [1,2] Therefore, the comparison of different systems representing the Kitatev model on different honeycomb-like lattices [3] is an important topic. We performed Raman scattering investigations on the continuum of fractionalized excitations to understand the role of symmetry, local distortions and dimensionality. In detail, we will report on data of α-RuCl3 as well as 2D/3D (Na,Li)2IrO3 and related compounds. Work supported by RTG-DFG 1952/1, the Laboratory for Emerging Nanometrology, TU Braunschweig, and NTH Contacs in Nanosystems.

[1] G. Jackeli and G. Khaliullin, Phys. Rev. Lett. 102, 017205 (2009); [2] M. Becker, M. Hermanns, B. Bauer, M. Garst and S. Trebst, Phys. Rev. B 91, 155135 (2015); [3] A. Glamazda, P. Lemmens, S.-H. Do, K.-Y. Choi, Nature Commun. 7, 12286 (2016).

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MA: Fachverband Magnetismus

MA 44: PhD Symposium Quantum Magnets (contributed talks)

MA 44.8: Vortrag, Mittwoch, 22. März 2017, 17:00–17:15, HSZ 403

Spectroscopic investigation of a spin liquid (RVB) state and local distortions in the frustrated spin-1/2 Copper Carbodiimide (CuNCN)Azat Sharafeev1, Vladimir Gnezdilov2, •Peter Lemmens1, Xiaohui Liu3, Andrei Tchougreeff3, and Richard Dronskowski31TU-BS, Braunschweig — 2ILTP, Kharkov — 3RWTH Aachen

In CuNCN there exist corrugated layers of Cu2+ bridged by NCN2- groups with a square planar Cu2+ coordination. Based on very large AF exchange and frustration a nonmagnetic ground state is observed. On the other side, some evidence for hidden magnetic order with strong fluctuations typical for low dimensionality has been given. We critically discuss the presently known scenarios on the basis of Raman scattering data, giving evidence for local lattice distortions for T<60K as well as high energy excitations. Work supported by RTG-DFG 1952/1, the Laboratory for Emerging Nanometrology, TU Braunschweig, and NTH Contacs in Nanosystems.

 

APS March Meeting 2017

Monday–Friday, March 13–17, 2017; New Orleans, Louisiana

Session K24: Spectroscopic Signatures of Fractionalized Excitations in Quantum Magnets

8:00 AM–11:00 AM, Wednesday, March 15, 2017
Room: New Orleans Theater C

Sponsoring Units: DCMP GMAG
Chair: Ioannis Rousochatzakis, University of Minnesota

Abstract: K24.00005 : Fractionalized Excitations in higher dimensional Iridates

10:24 AM–11:00 AM

Author: Peter Lemmens, Inst. Condensed Matter Physics, TU Braunschweig, Germany and Lab. for Emerging Nanometrology (LENA), TU Braunschweig, Germany

Fractionalization of elementary excitations remains an excotic phenomenon usually limited to 1D and 2D systems. Here we report spectroscopic signatures of fractional excitations in the 3D harmonic-honeycomb iridates beta - and gamma-LiIrO[1]. Our experimental evidence is based on Raman spectroscopic investigations of the polarization and temperature dependence of a scattering continuum, a comparison with earlier investigations of alpha-RuCl[2], and a comparison with theoretical modelling of the Kitatev model on different topologies [3]. [1] A. Glamazda, P. Lemmens, S.-H. Do, K.-Y. Choi, Nature Commun. 7, 12286 (2016). [2] L. J. Sandilands, Y. Tian, K. W. Plumb, Y. -J. Kim, and K. S. Burch, PRL 114, 147201 (2015). [3] J. Knolle, G.-W. Chern, D. L. Kovrizhin, R. Moessner, and N. B. Perkins, PRL 113, 187201 (2014). B. Perreault, J. Knolle, N. B. Perkins, and F. J. Burnell, PRB 92, 094439 (2015).