مطالعه‌ي ترابرد الكتريكي و ويژگي‌هاي توپولوژيكي نانونوارهاي 8-Pmmn بوروفين

Study of the electrical transport an‎d the topological properties of 8-Pmmn borophene nanoribbons

فيزيك ماده چگال

This study delves into the profound effects of tilted Dirac cones on the quantum transport properties of two-dimensional (2D) Dirac materials. These materials, characterized by their linear conical energy dispersion near Dirac points, exhibit unique electronic properties such as the presence of massless Dirac fermions an‎d relativistic phenomena like Klein tunneling. This research, expan‎ding beyond previous studies on graphene, focuses on materials with tilted Dirac cones. In these materials, the anisotropy an‎d tilting of the cones introduce additional complexity to their electronic behavior, which is associated with the specific spacetime structure underlying the material. Initially, the unique features of 2D materials such as graphene an‎d 8-Pmmn borophene, especially their transport properties an‎d tunneling phenomena, are explored. The study then proceeds to analyze a heterojunction of 2D Dirac materials, where electrons undergo quantum tunneling between regions with upright an‎d tilted Dirac cones. The role of the tilt in determining the transmission probability of electrons across these interfaces is thoroughly investigated. Furthermore, the impact of this tilt on the transmission an‎d reflection probabilities of the pseudospin of Dirac electrons, particularly under sudden changes in the tilt, is analyzed. Additionally, the reflection an‎d transmission probabilities through an intermediate slab with arbitrary subcritical tilt are examined, focusing on how the slab’s thickness influences the electron transmission between regions with varying Dirac cone tilts. The results indicate that for certain slab thicknesses, the transmission probability reaches unity. Both reflection an‎d transmission exhibit periodic behavior with respect to the slab thickness. These findings resemble Klein tunneling across potential barriers in PNP junctions, even in the absence of any applied gate voltage. The tilt-induced potential in tilted Dirac cones can be interpreted as the quantum transport manifestation of the "gravitomagnetic" effect arising from the underlying spacetime structure.

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