@Article{RodriguesJúniorMRRASGPM:2020:PsReRo,
               author = "Rodrigues J{\'u}nior, Gilberto and Marcal, Lucas Atila Bernardes 
                         and Ribeiro, Guliherme A. s. and Rappl, Paulo Henrique de Oliveira 
                         and Abramof, Eduardo and Sciammarella, Paulo Vitor and 
                         Guimar{\~a}es, Luciano de Moura and Perez, Carlos Alberto and 
                         Malachias, Angelo",
          affiliation = "{Universidade Federal de Minas Gerais (UFMG)} and {Universidade 
                         Federal de Minas Gerais (UFMG)} and {Universidade Federal de Minas 
                         Gerais (UFMG)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Universidade Federal de Vi{\c{c}}osa (UFV)} and {Universidade 
                         Federal de Vi{\c{c}}osa (UFV)} and {Laborat{\'o}rio Nacional de 
                         Luz S{\'{\i}}ncrotron (LNLS)} and {Universidade Federal de Minas 
                         Gerais (UFMG)}",
                title = "Direct observation of large strain through van der Waals gaps on 
                         epitaxial Bi2Te3/graphite: Pseudomorphic relaxation and the role 
                         of Bi-2 layers on the BixTey topological insulator series",
              journal = "Physical Review Materials",
                 year = "2020",
               volume = "4",
               number = "2",
                pages = "e023602",
                month = "Feb.",
             abstract = "Layered materials can usually grow without strain on top of 
                         distinct substrates if the only interaction between them is due to 
                         van der Waals forces. In such a scenario it would be expected that 
                         the heterointerface made up of weak bounds would not affect the 
                         overlayed material significantly for several large 
                         lattice-mismatched systems. Here we have studied the first stages 
                         of the heteroepitaxial growth of layered bismuth telluride 
                         topological insulator on top of highly oriented pyrolitic graphite 
                         (HOPG) by molecular beam epitaxy. Samples were investigated by 
                         atomic force microscopy (AFM), synchrotron x-ray diffraction 
                         (XRD), and micro-Raman spectroscopy. AFM images show 
                         hexagonal/triangular flat islands with exposed HOPG areas for the 
                         low coverage regime, and the lattice parameter of these Bi2Te3 
                         structures were measured by XRD. The existence of pseudomorphic 
                         strain at the initial Bi2Te3 layers was retrieved by both XRD and 
                         Raman spectroscopy. We have found evidence that Bi2Te3 layers near 
                         the interface are subject to an in-plane compressive strain, 
                         leading to a pseudomorphic out-of-plane lattice expansion. 
                         Furthermore, the presence of Bi2Te3 islands locally distorts the 
                         topmost layer of HOPG, resulting in tensile strain which was 
                         measured by Raman spectroscopy. The observed relaxation of 
                         0.1-0.2% for each van der Waals gap is used to calculate elastic 
                         constants of Bi-2 bilayers, which are crucial building blocks for 
                         the formation of other BixTey topological insulator compounds. 
                         Finally, the impact of such a strain in Bi2Te3 electronic 
                         structure was investigated by density functional theory 
                         calculations. The results show that the band structure of this 
                         strained material remains unchanged at the center of the Brillouin 
                         zone, confirming the robustness of surface states, but it is 
                         consistently affected at the M and K zone edges.",
                  doi = "10.1103/PhysRevMaterials.4.023602",
                  url = "http://dx.doi.org/10.1103/PhysRevMaterials.4.023602",
                 issn = "2475-9953",
             language = "en",
           targetfile = "PhysRevMaterials_v4_p023602_2020_Bi2Te3-HPOG.pdf",
        urlaccessdate = "28 abr. 2024"
}