期刊
PHYSICAL REVIEW B
卷 106, 期 8, 页码 -出版社
AMER PHYSICAL SOC
DOI: 10.1103/PhysRevB.106.085105
关键词
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资金
- U.S. DOE-BES [DE-FG02-04ER46148]
- CHPC at the University of Utah
- NERSC at the Office of Science of the U.S. Department of Energy
In this study, we systematically investigate the evolution of the band gap in a topological alloy as a function of alloy concentration using first-principles calculations. We found that the band gap in topological alloys exhibits a complex fragmented pattern and shows a linear dependence on concentration locally in each distinct phase. Moreover, we demonstrate that topological alloy engineering can be used as a general approach to tune the topological order.
Alloy engineering is a well-established approach to tune various materials' properties, but its application to topological alloys remains rudimentary. Of special interest is the band gap, the most defining property of topological materials; however, the concentration dependence of energy gaps in topological alloys remains unknown. Here we systematically investigate the band gap evolution of a topological alloy as a function of alloy concentration, using KZnSb1-xBix as a prototype, based on first-principles calculations. In contrast to the well-established smooth bowing curve for a trivial gap in semiconductor alloys, we found that the topological gap evolves generally with a complex fragmented pattern due to topological phase transitions, and most strikingly a linear dependence on concentration locally in each distinct phase. Such gap linearization is fundamentally rooted in the linear dependence on alloy concentration of spin-orbit coupling (SOC) that predominantly determines a topological gap. Furthermore, we demonstrate topological alloy engineering as a general approach to tune the topological order by modulating the band edge composition and degeneracy through the alloying-induced interplay of SOC and atomic orbital on-site energy, while the linear gap dependence on alloy concentration remains independent of the degree of topological order.
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