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Lee H, Han MJ, Chang KJ. Large-Gap and Topological Crystalline Insulating Phase in RbZnBi and CsZnBi. ACS OMEGA 2024; 9:29820-29828. [PMID: 39005786 PMCID: PMC11238197 DOI: 10.1021/acsomega.4c03506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/05/2024] [Accepted: 06/07/2024] [Indexed: 07/16/2024]
Abstract
Topological insulators (TIs) are a new class of materials with gapless boundary states inside the bulk insulating gap. This metallic boundary state hosts intriguing phenomena such as helical spin textures and Dirac crossing points. Here, we theoretically propose RbZnBi and CsZnBi as a new family of TIs exhibiting large bulk band gaps and unique gapless surface states. Our first-principles density functional calculations show that two materials can be stabilized in two different structures depending on the stacking order of hexagonal ZnBi layers. While both materials in the AA-stacked structure become TI, the AB-stacked RbZnBi and CsZnBi are topological crystalline insulators with hourglass-shaped Fermion surface states protected by nonsymmorphic glide symmetry. The calculated bulk gap is about 1.5-1.8 times larger than that of Bi2Se3, which makes RbZnBi and CsZnBi promising candidates for future applications.
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Affiliation(s)
- Hyunggeun Lee
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Myung Joon Han
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
| | - Kee Joo Chang
- Department of Physics, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Republic of Korea
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Gvozdetskyi V, Wang R, Xia W, Zhang F, Lin Z, Ho KM, Miller G, Zaikina JV. How to Look for Compounds: Predictive Screening and in situ Studies in Na-Zn-Bi System. Chemistry 2021; 27:15954-15966. [PMID: 34472129 PMCID: PMC9293119 DOI: 10.1002/chem.202101948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Indexed: 11/12/2022]
Abstract
Here, the combination of theoretical computations followed by rapid experimental screening and in situ diffraction studies is demonstrated as a powerful strategy for novel compounds discovery. When applied for the previously “empty” Na−Zn−Bi system, such an approach led to four novel phases. The compositional space of this system was rapidly screened via the hydride route method and the theoretically predicted NaZnBi (PbClF type, P4/nmm) and Na11Zn2Bi5 (Na11Cd2Sb5 type, P1‾
) phases were successfully synthesized, while other computationally generated compounds on the list were rejected. In addition, single crystal X‐ray diffraction studies of NaZnBi indicate minor deviations from the stoichiometric 1 : 1 : 1 molar ratio. As a result, two isostructural (PbClF type, P4/nmm) Zn‐deficient phases with similar compositions, but distinctly different unit cell parameters were discovered. The vacancies on Zn sites and unit cell expansion were rationalized from bonding analysis using electronic structure calculations on stoichiometric “NaZnBi”. In‐situ synchrotron powder X‐ray diffraction studies shed light on complex equilibria in the Na−Zn−Bi system at elevated temperatures. In particular, the high‐temperature polymorph HT‐Na3Bi (BiF3 type, Fm3‾m) was obtained as a product of Na11Zn2Bi5 decomposition above 611 K. HT‐Na3Bi cannot be stabilized at room temperature by quenching, and this type of structure was earlier observed in the high‐pressure polymorph HP‐Na3Bi above 0.5 GPa. The aforementioned approach of predictive synthesis can be extended to other multinary systems.
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Affiliation(s)
- Volodymyr Gvozdetskyi
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011, United States of Amerika
| | - Renhai Wang
- School of Physics and Optoelectronic Engineering, Guangdong University of Technology, Guangzhou, 510006, China.,Department of Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Weiyi Xia
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011, United States of Amerika
| | - Feng Zhang
- Ames Laboratory, U.S. Department of Energy, Ames, Iowa, 50011, United States of Amerika
| | - Zijing Lin
- Department of Physics, University of Science and Technology of China, Hefei, 230026, China
| | - Kai-Ming Ho
- Department of Physics and Astronomy, Iowa State University, Ames, Iowa, 50011, United States of Amerika
| | - Gordon Miller
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011, United States of Amerika
| | - Julia V Zaikina
- Department of Chemistry, Iowa State University, Ames, Iowa, 50011, United States of Amerika
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