Transport Properties of Hydrogenated Cubic Boron Nitride Nanofilms with Gold Electrodes from Density Functional Theory

Abstract

The electrical transport properties of a four-layered hydrogen-terminated cubic boron nitride sub-nanometer film in contact with gold electrodes are investigated via density functional calculations. The sample exhibits asymmetric metallic surfaces, a fundamental feature that triggers the system to behave like a typical p–n junction diode for voltage bias in the interval −0.2 ≤ V ≤ 0.2, where a rectification ratio up to 62 is verified. Further, in the wider region −0.3 ≤ V ≤ 0.3, negative differential resistance with a peak-to-valley ratio of 10 is observed. The qualitative behavior of the I – V characteristics is described in terms of the hydrogenated cBN film equilibrium electronic structure. Such a film shows metallic surfaces due to surface electronic states at a fraction of eV above and below the Fermi level of the N–H terminated and B–H terminated surfaces, respectively, with a wide bulk-band gap characteristic of BN materials. Such a mechanism is supported by transmission coefficient calculations, with the Landauer–Büttiker formula governing the I–V characteristics.

Charge and Spin Current Rectification through Functionalized Boron Nitride Bilayers

“…In the geometry shown in Figure a, the Au–Au bond length is 2.97 Å, and the B–N bond is 1.577 Å, which are values very close to the those obtained for cBN (1.56 Å,) and Au bulk (2.97 Å,) using DFT-PBE calculations. Therefore, it is possible to argue that the cBN film and the Au electrodes are nearly commensurate within the calculation precision …”

“…The unit cell vectors are a ( î 2 , 3 ĵ 2 ) and a ( − î 2 , 3 ĵ 2 ) , where a = 8.94 Å. The top electrode is composed of five Au planes oriented in the (111) direction, each plane containing nine atoms. , The left and right gold contacts are mirror images of each other, with an additional layer in the left contact (see Figure a). Such a layer is included only in the initial calculations with periodic boundary conditions that provide the initial guess for the density matrix used in the self-consistent transport calculations.…”

“…Therefore, it is possible to argue that the cBN film and the Au electrodes are nearly commensurate within the calculation precision. 18…”

“…Graphene possesses unique characteristics such as high mobility, resistance, and conductivity that have found a prominent position in the electronics, optoelectronics, spintronics, oil and gas industry, − and other fields. − The mechanical exfoliation technique, which is one of the most promising ways to achieve large-scale production at a low cost, , can produce other 2D materials besides graphene, contributing to the continuous expansion of the family of novel 2D materials. Single layers of boron nitride (BN), − silicon, , boron, Xenes, , germanium, phosphorus, , and transition-metal dichalcogenides − have been produced in the laboratory, , which have motivated further experimental and theoretical investigations, ,− leading to the observation of many interesting phenomena regarding structural/mechanical, electronic, and magnetic properties.…”

Modulation of spin and charge currents through functionalized 2D diamond devices

“…The atomic arrangement in which the 2D diamond is positioned between the electrodes is presented in figure 1(c). The supercell used in the transport calculations is periodic on the plane perpendicular to the transport direction and contains 99 atoms of Au, 12 O, 12 H, 24 B, and 24 N. The right Au slab is composed of five Au planes oriented in the (111) direction, each plane containing 9 atoms, resulting in a total of 45 Au atoms [55][56][57]. The left Au slab is a mirror image of the right electrode, with an additional layer of Au atoms (buffer atoms) used only in initial calculations with periodic boundary conditions that generate the initial density matrix for transport calculations.…”