Quantum Magnetotransport in Two-Dimensional Quartic Materials
Abstract
Two-dimensional (2D) materials attract attention not only because they promise enhanced performances, but also because they make it possible to realize novel and sometimes peculiar physical regimes. The most well-known example is graphene, in which low energy excitations have a linear dispersion, thus they behave like massless particles with an effective speed of light (linear, quadratic and quartic dispersions are shown in Figure 1). Owing to the linear dispersion, it becomes possible to observe Klein tunneling (an exotic effect enabling tunneling across opaque barriers with unit probability) with electrons of graphene on a bench-top experiment. On the other hand, almost all semiconductors materials (2D or otherwise) show good agreement with the effective mass approximation, which describes carriers with a quadratic energy dispersion. Therefore they display the normal tunneling . On the other hand, in quartic dispersion, energy is proportional to the fourth power of momentum, ie. . Such a dispersion relation gives rise to an unconventional tunneling behavior. In normal tunneling , tunneling probability decays with barrier width purely exponentially, whereas in quartic tunneling there is an oscillatory factor, as well. This not only brings a new regime for quantum transport in low-dimensional materials, but also paves alternative ways to control transport, which could then lead to novel device designs. In this project, we aim at uncovering the fundamentals of quartic tunneling and its possible control mechanisms with gating, magnetic field and strain.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 07, 2023
- Source ID
- FA95502110261
Entities
People
- Haldun Sevincli
Organizations
- Air Force Office of Scientific Research
- United States Air Force