Linking dynamics and kinetics of defect-doped spin chains and ladders

• Applicants: Professor Dr. Bernd Büchner; Professor Dr. Christian Hemker-Heß
• Subject Area: Experimental Condensed Matter Physics
• Term: from 2013 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 245897470

• Final Report Year: 2019

Final Report Abstract

The focus of this project was to experimentally investigate the impact of of impurities in low-dimensional quantum magnets on the ground state and the transport of elementary excitations by various methods, in particular neutron spectroscopy and thermal conductivity measurements. In the cuprate chain materials SrCuO2 and Sr2CuO3 it is confirmed that various in-chain impurities cause chain cuts, resulting in a global pseudogap behavior due to finite size effects. At the same time the spinon heat transport is strongly limited by the impurities. Furthermore, the heat transport of prototype low-dimensional quantum magnets with strong spin orbit coupling has been studied, revealing in particular a significant magnetic heat conductivity in the J eff=1/2 2D square lattice antiferromagnet Sr 2IrO4 and a sizeable thermal Hall effect in the Jeff=1/2 honeycomb Kitaev system α-RuCl3.

Publications

• Bond disorder and spinon heat transport in the S = 1∕2 Heisenberg spin chain compound Sr2CuO3: from clean to dirty limits, Phys. Rev. B 89, 104302 (2014)
  A. Mohan, N. Sekhar Beesetty, N. Hlubek, R. Saint-Martin, A. Revcolevschi, B. Büchner, C. Hess
  
• Suppression of the impurity-induced local magnetism by the opening of a spin pseudogap in Nidoped Sr2CuO3, Phys. Rev. B 92, 060405(R) (2015)
  Y. Utz, F. Hammerath, S. Nishimoto, C. Hess, N. S. Beesetty, R. Saint-Martin, A. Revcolevschi, B. Büchner, H. Grafe
  
• Magnetic ordering in the ultrapure site-diluted spin chain materials SrCu 1-xNixO2, Phys. Rev. B 93, 214430 (2016)
  G. Simutis, M. Thede, R. Saint-Martin, A. Mohan, C. Baines, Z. Guguchia, R. Khasanov, C. Hess, A. Revcolevschi, B. Büchner, A. Zheludev
  
• Pseudospin transport in the Jeff= 1∕2 antiferromagnet Sr2IrO4, EPL (Europhysics Letters) 114, 57007 (2016)
  F. Steckel, A. Matsumoto, T. Takayama, H. Takagi, B. Büchner, C. Hess
  
• Effect of different in-chain impurities on the magnetic properties of the spin chain compound Sr- CuO2 probed by NMR, Phys. Rev. B 96, 115135 (2017)
  Y. Utz, F. Hammerath, R. Kraus, T. Ritschel, J. Geck, L. Hozoi, J. van den Brink, A. Mohan, C. Hess, K. Karmakar, S. Singh, D. Bounoua, R. Saint-Martin, L. Pinsard- Gaudart, A. Revcolevschi, B. Büchner, H. Grafe
  
• Spin pseudogap in the S = 1∕2 chain material Sr 2CuO3 with impurities, Phys. Rev. B 95, 054409 (2017)
  G. Simutis, S. Gvasaliya, N. S. Beesetty, T. Yoshida, J. Robert, S. Petit, A. I. Kolesnikov, M. B. Stone, F. Bourdarot, H. C. Walker, D. T. Adroja, O. Sobolev, C. Hess, T. Masuda, A. Revcolevschi, B. Büchner, A. Zheludev
  
• Unusual Phonon Heat Transport in α-RuCl3: Strong Spin-Phonon Scattering and Field-Induced Spin Gap, Phys. Rev. Lett. 120, 117204 (2018)
  R. Hentrich, A. U. B. Wolter, X. Zotos, W. Brenig, D. Nowak, A. Isaeva, T. Doert, A. Banerjee, P. Lampen-Kelley, D. G. Mandrus, S. E. Nagler, J. Sears, Y.-J. Kim, B. Büchner, C. Hess
  
• Heat transport of cuprate-based low-dimensional quantum magnets with strong exchange coupling, Physics Reports (2019)
  C. Hess
  
• Large Thermal Hall Effect in α-RuCl3: Evidence for Heat Transport by Kitaev-Heisenberg Paramagnons, Phys. Rev. B 99, 085136 (2019)
  R. Hentrich, M. Roslova, A. Isaeva, T. Doert, W. Brenig, B. Büchner, C. Hess