Agradecimentos: We acknowledge constructive discussions with Z. Fisk, S. Wirth, J. Muller, O. Erten and C. Kurdak. Synthesis and macroscopic measurements at low fields were supported by the U.S. Department of Energy (DOE) BES "Quantum Fluctuations in Narrow-Band Systems" project. High-field...

Agradecimentos: We acknowledge constructive discussions with Z. Fisk, S. Wirth, J. Muller, O. Erten and C. Kurdak. Synthesis and macroscopic measurements at low fields were supported by the U.S. Department of Energy (DOE) BES "Quantum Fluctuations in Narrow-Band Systems" project. High-field magnetization measurements were supported by the DOE BES "Science of 100 Tesla" project. S.K. acknowledges support from the LANL Director’s Postdoctoral LDRD program. The National High Magnetic Field Laboratory is supported by the National Science Foundation through NSF/DMR-1644779 and the State of Florida. Scanning electron microscope and energy dispersive X-ray measurements were performed at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the DOE Office of Science. Electron spin resonance measurements were supported by FAPESP (SP-Brazil) grants no. 2018/11364-7, 2017/10581-1, 2012/04870-7, CNPq Grant no. 141026/2017-0, CAPES and FINEP-Brazil. We thank Diamond Light Source for the provision of beamtime under proposal MT18991. Work at UCL is supported by the UK Engineering and Physical Sciences Research Council (Grants No. EP/N027671/1 and No. EP/N034694/1) Theory efforts were supported by DOE de-sc0016239, NSF EAGER 1004957, Simons Investigator Grants, ARO MURI W911NF- 12-1-0461, the Packard Foundation, and the Schmidt Fund for Innovative Research. Y.X. and A. Bernevig were supported by Max Planck society. Z.W. received support from the National Natural Science Foundation of China (No. 11974395), the Chinese Academy of Sciences (CAS) (Grant No. XDB33000000), and the CAS Pioneer Hundred Talents Program

Abstract: Here we investigate antiferromagnetic Eu5In2Sb6, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu5In2Sb6 is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, which is consistent with the presence of magnetic polarons. From ab...

Abstract: Here we investigate antiferromagnetic Eu5In2Sb6, a nonsymmorphic Zintl phase. Our electrical transport data show that Eu5In2Sb6 is remarkably insulating and exhibits an exceptionally large negative magnetoresistance, which is consistent with the presence of magnetic polarons. From ab initio calculations, the paramagnetic state of Eu5In2Sb6 is a topologically nontrivial semimetal within the generalized gradient approximation (GGA), whereas an insulating state with trivial topological indices is obtained using a modified Becke-Johnson potential. Notably, GGA+U calculations suggest that the antiferromagnetic phase of Eu5In2Sb6 may host an axion insulating state. Our results provide important feedback for theories of topological classification and highlight the potential of realizing clean magnetic narrow-gap semiconductors in Zintl materials

FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP

2017/10581-1; 2012/04870-7; 2018/11364-7

CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ

141026/2017-0

Aberto