Metallic islands in the Kondo insulator SmB_{6}
The predicted interplay between Kondo physics and nontrivial topology in SmB_{6} 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/o...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2020-11-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.2.043181 |
| _version_ | 1797211206337953792 |
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| author | J. C. Souza P. F. S. Rosa J. Sichelschmidt M. Carlone P. A. Venegas M. O. Malcolms P. M. Menegasso R. R. Urbano Z. Fisk P. G. Pagliuso |
| author_facet | J. C. Souza P. F. S. Rosa J. Sichelschmidt M. Carlone P. A. Venegas M. O. Malcolms P. M. Menegasso R. R. Urbano Z. Fisk P. G. Pagliuso |
| author_sort | J. C. Souza |
| collection | DOAJ |
| description | The predicted interplay between Kondo physics and nontrivial topology in SmB_{6} 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 Gd^{3+}. In this work, we locally investigate this fragility for Al flux grown Sm_{1−x}Gd_{x}B_{6} single crystals (0≤x≤0.02) by combining electron spin resonance (ESR) and complementary bulk measurements. The Gd^{3+} ESR spectra in a highly dilute regime (x∼0.0004) display the features of an insulating cubic environment. Remarkably, a metallic ESR line shape is observed for more concentrated samples (x≥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. |
| first_indexed | 2024-04-24T10:22:48Z |
| format | Article |
| id | doaj.art-62c9cb18e85c40bfa671c342ec346e0b |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:22:48Z |
| publishDate | 2020-11-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-62c9cb18e85c40bfa671c342ec346e0b2024-04-12T17:03:25ZengAmerican Physical SocietyPhysical Review Research2643-15642020-11-012404318110.1103/PhysRevResearch.2.043181Metallic islands in the Kondo insulator SmB_{6}J. C. SouzaP. F. S. RosaJ. SichelschmidtM. CarloneP. A. VenegasM. O. MalcolmsP. M. MenegassoR. R. UrbanoZ. FiskP. G. PagliusoThe predicted interplay between Kondo physics and nontrivial topology in SmB_{6} 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 Gd^{3+}. In this work, we locally investigate this fragility for Al flux grown Sm_{1−x}Gd_{x}B_{6} single crystals (0≤x≤0.02) by combining electron spin resonance (ESR) and complementary bulk measurements. The Gd^{3+} ESR spectra in a highly dilute regime (x∼0.0004) display the features of an insulating cubic environment. Remarkably, a metallic ESR line shape is observed for more concentrated samples (x≥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.http://doi.org/10.1103/PhysRevResearch.2.043181 |
| spellingShingle | J. C. Souza P. F. S. Rosa J. Sichelschmidt M. Carlone P. A. Venegas M. O. Malcolms P. M. Menegasso R. R. Urbano Z. Fisk P. G. Pagliuso Metallic islands in the Kondo insulator SmB_{6} Physical Review Research |
| title | Metallic islands in the Kondo insulator SmB_{6} |
| title_full | Metallic islands in the Kondo insulator SmB_{6} |
| title_fullStr | Metallic islands in the Kondo insulator SmB_{6} |
| title_full_unstemmed | Metallic islands in the Kondo insulator SmB_{6} |
| title_short | Metallic islands in the Kondo insulator SmB_{6} |
| title_sort | metallic islands in the kondo insulator smb 6 |
| url | http://doi.org/10.1103/PhysRevResearch.2.043181 |
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