Tunable Dirac cone in the rectangular symmetrical semiconductor quantum dots array

We studied the electronic properties of a two-dimensional (2D) rectangular symmetrical semiconductor quantum dots (QD) lattice and found a type of tunable Dirac cone structure in its energy spectrum by using tight-binding method. We show that, by tuning the parameters of the QD lattice, the energy gap could be closed and form the Dirac cone. A phase diagram of transition from the gap opening to the gapless state is also obtained. Furthermore, we found the Dirac cone is anisotropic, implying direction-dependent electronic properties and conductivities. These findings may be useful for the development and application of high-speed semiconductor QD devices.