Quantum electronic transport in 2D systems

Projects carried out as part of a research internship at the Autonomous University of Baja California under the supervision of Dr. Ramon Carrilo Bastos as part of the XXVII Pacific Summer of Scientific and Technological Research 2022 of the Delfin program.

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Graphene has been the subject of a great deal of scientific work, the reason for this is due to its electronic and transport properties. One of these properties is that the electrons in it behave as massless relativistic fermions, described by the Dirac equation; this initiated the study of a new class of materials: two-dimensional materials.

Due to the unique properties of graphene, the search for other systems in which electrons behave as massless Dirac fermions has increased in recent years. These kinds of systems, known as Dirac systems, share characteristics such as optical conductivity and high heat capacity, to name a few.

Among the Dirac systems is Kekulé-distorted graphene, which consists of a periodic distribution of strong and weak bonds in the graphene lattice that causes the unit cell to triple with respect to that of pristine graphene. Another Dirac system is the α-T3 model, which consists of the graphene lattice with the addition of a site in the center of each hexagon which is coupled to neighboring atoms of only one of the sublattices, this model has a band structure identical to that of graphene with the exception that it has an additional band, a flat band.

The α-T₃ model with Kekulé periodicity

Motivated by the Dirac systems mentioned above, we can construct a hybrid model, the α-T3 model with Kekulé periodicity, i.e., the sites at the centers of the hexagons appear with Kekulé periodicity.