Osaka University researchers have found that the electronic surface structure of samarium hexaboride, taken from the electronic bulk structure topology, can be controlled by changing the surface condition. Their findings could lead to new technologies for higher-speed electronics.
Topologically protected shapes, such as a Möbius strip, cannot be modified without breaking them through methods such as cutting. Osaka University researchers have developed a new way to alter electronic surface structures, bypassing topological protection.
Physicists believe that metal surface states of topological insulators are very stable because the surface states are protected by the wavefunction symmetry of the massive electronic structure. This property is an important advantage for applied products used in different environments; however, this property also means that it is difficult to control the surface condition based on one’s purpose.
“This was considered beneficial, for example to avoid contamination effects,” said lead author Yoshiyuki Ohtsubo, “but we found that the topologically protected surface states can be checked by changing the surface symmetry without touching the inside, which will be a new method of checking for topological electronic states useful to quantum computers and other advanced technologies.”
A groundbreaking result of this research is that the electronic structure of a slightly tilted surface from the bulk plane of symmetry of monocrystalline samarium hexaboride (SmB6) is not the same symmetry as the bulk. This result indicates that a different topological surface state has been created by fabricating this new atomic surface structure.
“In other words, the electronic structure of the surface and the conductive property can be controlled through manufacturing methods,” explains Shin-Ichi Kimura, senior author. “This will serve as a method to monitor topologically protected electronic structures and their physical properties.”
This research result has revealed that the topological surface electronic state, which was thought to be “strictly” determined by bulk symmetry, has many degrees of freedom and can be “flexibly” controlled by manipulating the atomic structure of the surface. This achievement is expected to be applied to next-generation low-power, high-speed devices that use the same electronic state, as well as to information transfer in quantum computers.
The article, “Breakdown of Bulk Projected Isotropy in Electronic Surface States of Topological Kondo Insulator SmB6(001),” was published in nature communication.
Settling the debate: solving the electronic surface states of samarium hexaboride
Yoshiyuki Ohtsubo et al, Breakdown of Bulk Projected Isotropy in Electronic Surface States of Topological Kondo Insulator SmB6(001), nature communication (2022). DOI: 10.1038/s41467-022-33347-0
Quote: Engineering Surface Atomic Structures for Next Generation Electronics (2022, September 30) Retrieved September 30, 2022 from https://phys.org/news/2022-09-surface-atomic-next-generation-electronics.html
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