First-principles study on electronic properties of twisted bilayer borophene

Borophene has received considerable investigations in recent five years that it is reported to possess a series of marvelous properties. However, most of the researches are about its monolayer form, the bilayer borophene, especially the twisted bilayer form which is a hot topic recently, has not been studied in detail. Herein, the first-principles calculations based on the density functional theory (DFT) method was performed to study the electronic properties of three kinds of twisted bilayer borophene that each kind of bilayer borophene is twisted to a certain angle in the plane. For the consideration of structural stability and calculation cost, the bilayer borophene are optimized to be 32.2°, 58.0° and 83.6° using an algorithm based on crystal matching theory. The charge density of relaxed twisted bilayer borophene shows the proximity of boron atoms. The analysis of band structure reveals that the twisted bilayer structure could separate the degenerate band and transform the bands to direct type, thus, modulating the resistance. In addition, a near-zero density of states could be found when bilayer borophene is twisted. This research could provide a basis for the applications of borophene, such as integrated electronic devices and micro/nano electronics.