Bulk transport paths through defects in floating zone and Al flux grown ${\mathrm{SmB}}_{6}$

Bulk transport paths through defects in floating zone and Al flux grown ${SmB}_{6}$

Yun Suk Eo, Alexa Rakoski, Shriya Sinha, Dmitri Mihaliov, Wesley T. Fuhrman, Shanta R. Saha, Priscila F. S. Rosa, Zachary Fisk, Monica Ciomaga Hatnean, Geetha Balakrishnan, Juan R. Chamorro, W. Adam Phelan, Seyed M. Koohpayeh, Tyrel M. McQueen, Boyoun Kang, Myung-suk Song, Beongki Cho, Michael S. Fuhrer, Johnpierre Paglione, and Çağlıyan Kurdak

Phys. Rev. Materials 5, 055001 – Published 7 May 2021

Abstract

We investigate the roles of disorder on low-temperature transport in $Sm B_{6}$ crystals grown by both the Al flux and floating zone methods. We used the inverted resistance method with Corbino geometry to investigate whether low-temperature variations in the standard resistance plateau arise from a surface or a bulk channel in floating zone samples. The results show significant sample-dependent residual bulk conduction, in contrast to smaller amounts of residual bulk conduction previously observed in Al flux grown samples with Sm vacancies. We consider hopping in an activated impurity band as a possible source for the observed bulk conduction, but it is unlikely that the large residual bulk conduction seen in floating zone samples is solely due to Sm vacancies. We therefore propose that one-dimensional defects, or dislocations, contribute as well. Using chemical etching, we find evidence for dislocations in both flux and floating zone samples, with higher dislocation density in floating zone samples than in Al flux grown samples. In addition to the possibility of transport through one-dimensional dislocations, we also discuss our results in the context of recent theoretical models of $Sm B_{6}$ .

Received 20 November 2020
Accepted 24 March 2021

DOI:https://doi.org/10.1103/PhysRevMaterials.5.055001

Physics Subject Headings (PhySH)

Disclinations & dislocations Impurities Transport phenomena

Strongly correlated systems

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Yun Suk Eo^1,2,*,†, Alexa Rakoski ^1,*,‡, Shriya Sinha¹, Dmitri Mihaliov ¹, Wesley T. Fuhrman^2,3, Shanta R. Saha², Priscila F. S. Rosa⁴, Zachary Fisk⁵, Monica Ciomaga Hatnean ⁶, Geetha Balakrishnan ⁶, Juan R. Chamorro³, W. Adam Phelan^3,7,4,8, Seyed M. Koohpayeh^3,7, Tyrel M. McQueen^3,8,7, Boyoun Kang⁹, Myung-suk Song⁹, Beongki Cho⁹, Michael S. Fuhrer ^10,11, Johnpierre Paglione^2,12, and Çağlıyan Kurdak ¹

¹Department of Physics, University of Michigan, Ann Arbor, Michigan 48109, USA
²Maryland Quantum Materials Center and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
³Institute for Quantum Matter and Department of Physics and Astronomy, Johns Hopkins University, Baltimore, Maryland 21218, USA
⁴Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
⁵Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
⁶Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
⁷Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA
⁸Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, USA
⁹Department of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
¹⁰School of Physics and Astronomy, Monash University, Monash, Victoria 3800, Australia
¹¹ARC Centre of Excellence in Future Low-Energy Electronics Technologies, Monash University, Victoria 3800, Australia
¹²Canadian Institute for Advanced Research, Toronto, Ontario, Canada M5G 1Z8