Kondo Insulator to Semimetal Transformation Tuned by Spin-Orbit Coupling
| Autor: | G. Eguchi, Sami Dzsaber, Andrey Sidorenko, Lukas Prochaska, Robert Svagera, Silke Paschen, Qimiao Si, Andrey Prokofiev, M. Waas |
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| Rok vydání: | 2016 |
| Předmět: |
Physics
Condensed matter physics Strongly Correlated Electrons (cond-mat.str-el) Kondo insulator General Physics and Astronomy FOS: Physical sciences 02 engineering and technology Spin–orbit interaction 021001 nanoscience & nanotechnology Coupling (probability) Lambda 01 natural sciences Semimetal Condensed Matter - Strongly Correlated Electrons 0103 physical sciences Condensed Matter::Strongly Correlated Electrons Kondo effect Isostructural 010306 general physics 0210 nano-technology Ground state |
| Zdroj: | Physical review letters. 118(24) |
| ISSN: | 1079-7114 |
| Popis: | Recent theoretical studies of topologically nontrivial electronic states in Kondo insulators have pointed to the importance of spin-orbit coupling (SOC) for stabilizing these states. However, systematic experimental studies that tune the SOC parameter $\lambda_{\rm{SOC}}$ in Kondo insulators remain elusive. The main reason is that variations of (chemical) pressure or doping strongly influence the Kondo coupling $J_{\text{K}}$ and the chemical potential $\mu$ -- both essential parameters determining the ground state of the material -- and thus possible $\lambda_{\rm{SOC}}$ tuning effects have remained unnoticed. Here we present the successful growth of the substitution series Ce$_3$Bi$_4$(Pt$_{1-x}$Pd$_x$)$_3$ ($0 \le x \le 1$) of the archetypal (noncentrosymmetric) Kondo insulator Ce$_3$Bi$_4$Pt$_3$. The Pt-Pd substitution is isostructural, isoelectronic, and isosize, and therefore likely to leave $J_{\text{K}}$ and $\mu$ essentially unchanged. By contrast, the large mass difference between the $5d$ element Pt and the $4d$ element Pd leads to a large difference in $\lambda_{\rm{SOC}}$, which thus is the dominating tuning parameter in the series. Surprisingly, with increasing $x$ (decreasing $\lambda_{\rm{SOC}}$), we observe a Kondo insulator to semimetal transition, demonstrating an unprecedented drastic influence of the SOC. The fully substituted end compound Ce$_3$Bi$_4$Pd$_3$ shows thermodynamic signatures of a recently predicted Weyl-Kondo semimetal. Comment: 6 pages, 5 figures plus Supplemental Material |
| Databáze: | OpenAIRE |
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