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Ab initio study of the electronic and thermoelectric properties monolayer ππ§ππ, ππππ and ππ§πππππ
H. Elsayed1, D. OlguΓn2, and A. Cantarero3
1 Programa de Nanociencias y NanotecnologΓa, Centro de Investigacion y de Estudios Avanzados del Instituto PolitΓ©cnico Nacional, Ciudad de Mexico 07360, Mexico.
2 Depatamento de FΓsica, Centro de Investigacion y de Estudios Avanzados del Instituto PolitΓ©cnico Nacional, QuerΓ©taro 76230, Mexico.
3Molecular Science Institute, University of Valencia, Valencia 46071, Spain.
1. Introduction- we have studied the electronic and thermoelectric properties, Seebeck coefficient, powerfactor, electrical conductivity, and electronic thermal conductivity, of one layer of ππ§ππ, ππππand ππ§πππππ
[1], the heterostructure constructed by simultaneously stacking an ππ§ππ layer and a ππππ layerbounded by van der Waals forces, and compared them with the corresponding properties in the bulk case ofeach material. Our study is based on the density functional theory (DFT) [2,3]. We have used the full-potentiallinearized augmented plane-wave (FLAPW) method as implemented in the Wien2k code [4], to calculate theelectronic structure. From the results of the electronic properties, the thermoelectric properties have beencalculated using the semi-classical Boltzmann theory and the rigid band approach as implemented in theBoltzTrap code [5].
2. Results and discussion β In all the studied materials moving from the 3D cases to the 2D case, there is agreat enhancement in the values of the Seebeck coefficient in comparison with the bulk cases. This could beattributed to the quantum confinement effect or the sharp increase in the total density of states at the fermilevel. The contrary has been found for the electrical conductivity since its values were better in the bulk cases.From the values of the Seebeck coefficient and the electrical conductivity, the power factor have beencalculated. It has been found that in spite of the lower values of the electrical conductivity in the monolayercase, the values of the power factor were better in the monolayer cases. Further it has been observed that thevalues of the thermal conductivity were smaller in the monolayer cases.
3. Conclusion β we can conclude that the studied materials could be preferable as a good thermoelectricmaterials in the low dimension structure than in the bulk.
4. References
[1] W. Ibarra-HernΓ‘ndez, H. Elsayed, A. H. Romero, A. Bautista-HernΓ‘ndez, D. OlguΓn and A. Cantarero.Phys. Rev. B 96 (2017), 035201.
[2] P. Hohenberg and W. Kohn. Phys. Rev.136 (1964), B864βB871.
[3] W. Kohn and L. J. Sham. Phys. Rev.140 (1965), A1133βA1138.
[4] P.Blaha, K.Schwarz, G.K.H.Madsen, D.Kvasnicka, J.Luitz, Vienna University of Technology, Austria(2001).
[5] G.K.H. Madsen, D.J.Singh, Comput. Phys. Commun.175 (2006) 67.
M&Ns-19, Paris, 17-19 July 2019 Pag. 124
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