There is a growing interest in the property dependence of transition metal dichalcogenides as function of the number of layers and formation of heterostructures. Depending on the stacking, doping, edge effects and interlayer distance, the properties can be modified, which open the door to novel applications which require a detailed understanding of the atomic mechanisms responsible for those changes. In this work, we analyze the electronic properties and lattice dynamics of a heterostructure constructed by simultaneously stacking InSe layers and GaSe layers bounded by van der Waals forces. We have assumed the same space group of GaSe, P6m2 as it becomes the lower energy configuration for other considered stackings. The structural, vibrational and optical properties of this layered compound have been calculated using density functional theory. The structure is shown to be energetically, thermally and elastically stable, which indicates its possible chemical synthesis. A correlation of the theoretical physical properties with respect to its parent compounds is extensively discussed. One of the most interesting properties is the low thermal conductivity, which indicates its potential use in thermolectric applications. Additionally, we discuss the possibility of using electronic gap engineering methods, which can help into tune the optical emission in a variable range close to that used in the field of biological systems (NIR). Finally, the importance of considering properly van der Waals dispersion in layered materials has been emphasized as included in the exchange correlation functional. As for the presence of atoms with important spin orbit coupling, relativistic corrections have been included.

We present a careful and detailed ab initio study of the crystal structure and electronic band structure of different crystalline phases of MgSe. Calculations were performed using the full‐potential linear augmented plane wave method. To determine the crystal phase of the ground state of MgSe, we computed the total energy as a function of volume for the rock‐salt, zinc‐blende, wurtzite, and NiAs phases. From the optimized volume, and by using the Birch–Murnaghan equation of state the lattice parameters a0 false(c0false), the bulk moduli, and its first pressure derivative (B0 normaland B0′) for the different phases of MgSe were found. In our calculations, we have used the local density approach for the exchange–correlation part of the total energy. It was determined that in this approach the sequence of phase transformations under pressure is rock‐salt–NiAs–wurzite–zinc‐blende. However, we also found that under ambient conditions, the different studied phases for MgSe are energetically available. Using the modified Becke–Johnson exchange correlation potential, the calculated values of the bandgap were improved, and the results are comparable to existing experimental values for the zinc‐blende phase.

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