Electronic properties of low-dimensional materials under mechanical deformation
- Low-dimensional materials utilized in nanoelectronics, inevitably undergo structural deformations during the device manufacturing processes. These mechanical deformations can significantly modify the intrinsic electronic properties of the materials. Therefore, the optimal design of electronic devices at nanometric scale demands a deep understanding of the effects of mechanical deformations on the electric structure of the nanosystems. In addition, the interplay between mechanical and electronic properties can advantageously be used to tune the material characteristics for optimizing the device performance.
In this work, mechanical deformations were deliberately introduced to low-dimensional materials as a strategy to tune their electronic properties. In particular, elastic deformations of carbon nanotubes, graphene, metal organic frameworks (MOFs), and SiGe thin films were simulated using quantum mechanical methods. The results from these simulations indicate that the elastic indentation applied to metallic carbon nanotubes and graphene do not change their metallic character, whereas in the case of semiconducting carbon tubes, the same type of deformation reduces significantly their intrinsic band gap, by up to 60%. Nevertheless, no transport channels for the conductance are opened due to these reversible structural distortions. Further, applying uniaxial strain to a particular type of metal organic frameworks, namely MOF-2, results in a decrease in the effective mass of the charge carriers, which can be understood as an enhancement of their charge carrier mobility. In the case of SiGe monolayers, elastic strain induces a band inversion between the valence and conduction bands, causing a nontrivial topological phase transition.