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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Metallic islands in the Kondo insulator SmB6

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Author(s):
Souza, J. C. [1, 2] ; Rosa, P. F. S. [3] ; Sichelschmidt, J. [2] ; Carlone, M. [4] ; Venegas, P. A. [5] ; Malcolms, M. O. [1] ; Menegasso, P. M. [1] ; Urbano, R. R. [1] ; Fisk, Z. [6] ; Pagliuso, P. G. [1]
Total Authors: 10
Affiliation:
[1] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil
[2] Max Planck Inst Chem Phys Solids, D-01187 Dresden - Germany
[3] Los Alamos Natl Lab, Los Alamos, NM 87545 - USA
[4] UNESP, Fac Ciencias, POSMAT, CP 473, BR-17033360 Bauru, SP - Brazil
[5] UNESP, Fac Ciencias, Dept Fis, CP 473, BR-17033360 Bauru, SP - Brazil
[6] Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 - USA
Total Affiliations: 6
Document type: Journal article
Source: PHYSICAL REVIEW RESEARCH; v. 2, n. 4 NOV 3 2020.
Web of Science Citations: 0
Abstract

The predicted interplay between Kondo physics and nontrivial topology in SmB6 has stimulated many experimental reports, some of which are in apparent contradiction. The origin of the dispute may lie in the fragility of the Kondo insulating phase in the presence of Sm vacancies (Kondo holes) and/or natural impurities, such as Gd3+. In this work, we locally investigate this fragility for Al flux grown Sm1-xGdxB6 single crystals (0 <= x <= 0.02) by combining electron spin resonance (ESR) and complementary bulk measurements. The Gd3+ ESR spectra in a highly dilute regime (x similar to 0.0004) display the features of an insulating cubic environment. Remarkably, a metallic ESR line shape is observed for more concentrated samples (x similar to 0.004), even though these systems are still in a reasonably dilute regime and show insulating dc electrical resistivity. Our data indicate that the Kondo insulating state is destroyed locally around impurities before a global percolation occurs. This result not only explains the discrepancy between dc and ac conductivity but also provides a scenario to explain the presence of quantum oscillations in magnetization in the absence of quantum oscillations in electrical resistivity. (AU)

FAPESP's process: 12/04870-7 - Studies of novel complex and advanced materials
Grantee:Pascoal Jose Giglio Pagliuso
Support type: Research Projects - Thematic Grants
FAPESP's process: 16/14436-3 - Studies of electronic and magnetic correlation in iron based superconductors and molecular conductors via Nuclear Magnetic Ressonance (NMR) and Quadrupolar (NQR)
Grantee:Paulo Eduardo Menegasso Filho
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 17/10581-1 - Emergent phenomena in reduced dimension systems
Grantee:Pascoal Jose Giglio Pagliuso
Support type: Research Projects - Thematic Grants
FAPESP's process: 12/05903-6 - Nuclear magnetic resonance of novel complex and advanced materials in condensed matter physics
Grantee:Ricardo Rodrigues Urbano
Support type: Research Grants - Young Investigators Grants
FAPESP's process: 18/11364-7 - Magnetic properties of complex systems with non-trivial topology
Grantee:Jean Carlo Souza
Support type: Scholarships in Brazil - Doctorate