Thermal Transport and Strong Mass Renormalization in ${\mathrm{NiCl}}_{2}\mathrm{\text{\ensuremath{-}}}4\mathrm{SC}({\mathrm{NH}}_{2}{)}_{2}$

Thermal Transport and Strong Mass Renormalization in ${NiCl}_{2} − 4 SC ({NH}_{2})_{2}$

Y. Kohama, A. V. Sologubenko, N. R. Dilley, V. S. Zapf, M. Jaime, J. A. Mydosh, A. Paduan-Filho, K. A. Al-Hassanieh, P. Sengupta, S. Gangadharaiah, A. L. Chernyshev, and C. D. Batista

Phys. Rev. Lett. 106, 037203 – Published 18 January 2011

Abstract

Several quantum paramagnets exhibit magnetic-field-induced quantum phase transitions to an antiferromagnetic state that exists for $H_{c 1} \leq H \leq H_{c 2}$ . For some of these compounds, there is a significant asymmetry between the low- and high-field transitions. We present specific heat and thermal conductivity measurements in ${NiCl}_{2} − 4 SC ({NH}_{2})_{2}$ , together with calculations which show that the asymmetry is caused by a strong mass renormalization due to quantum fluctuations for $H \leq H_{c 1}$ that are absent for $H \geq H_{c 2}$ . We argue that the enigmatic lack of asymmetry in thermal conductivity is due to a concomitant renormalization of the impurity scattering.

Received 19 August 2010

DOI:https://doi.org/10.1103/PhysRevLett.106.037203

Authors & Affiliations

Y. Kohama¹, A. V. Sologubenko², N. R. Dilley³, V. S. Zapf¹, M. Jaime¹, J. A. Mydosh⁴, A. Paduan-Filho⁵, K. A. Al-Hassanieh⁶, P. Sengupta⁷, S. Gangadharaiah^8,9, A. L. Chernyshev^8,9, and C. D. Batista⁶

¹MPA-CMMS, LANL, Los Alamos, New Mexico 87545, USA
²II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, 50937 Köln, Germany
³Quantum Design Inc., San Diego, California 92121, USA
⁴Kamerlingh Onnes Laboratory, Leiden University, 2300RA Leiden, The Netherlands
⁵Instituto de Fisica, Universidade de Sao Paulo, Brazil
⁶Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
⁷School of Physical and Mathematical Sciences, Nanyang Technological University, 50 Naynag Avenue, Singapore 639798
⁸Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
⁹Max-Planck-Institut für Physik komplexer Systeme, Nöthnitzer Straße 38, 01187 Dresden, Germany