Mechanical properties of Bi2Te3 topological insulator investigated by density functional theory and nanoindentation

Elastic constants determination of anisotropic materials by depth-sensing indentation

“…The function h ( ) is calculated from Eqs. (11)(12)(13)(14)(15). However, due to symmetry properties of the transversely isotropic material, no numerical integration is needed, and an explicit equation for h ( ) is obtained using a first order approximation of the Fourier series:…”

“…3) were used to validate computational results from density functional theory (DFT) on the evaluation of the elastic constants of the topological insulator Bi 2 Te 3 . Further details about the results discussed herein can be found in the work from Lamuta et al [15]. 3D topological insulators are considered a novel topological phase of matter, and are gaining growing interest from the worldwide scientific community [16][17][18], due to their promising applications in optoelectronics [19], plasmonics [20], spintronics [21], quantum computing [22], and thermoelectric devices [17,23,24].…”

“…3D topological insulators are considered a novel topological phase of matter, and are gaining growing interest from the worldwide scientific community [16][17][18], due to their promising applications in optoelectronics [19], plasmonics [20], spintronics [21], quantum computing [22], and thermoelectric devices [17,23,24]. Bi 2 Te 3 and Bi 2 Se 3 represent the most studied topological insulators, due to their large energy gap (~ 0.2-0.3 eV) that allows applications at room temperature [15,[25][26][27][28][29]. In this section we focus on Bi 2 Te 3 , a layered and anisotropic material, whose atomic structure is illustrated in Fig.…”

“…Lamuta et al [15] calculated the elastic properties of Bi 2 Te 3 by means of DFT simulations. A rhombohedral unit cell was used to simulate the topological insulator (shown in Fig.…”

“…Lamuta et al [15], considered the approximation of a circular contact area, and used Eq. (18) to calculate the indentation modulus along 2 different directions, parallel and perpendicular to the material lamellae (i.e., each lamella corresponds to a quintuple layer (QL), and lies in the Bi 2 Te 3 basal plane), respectively.…”