RESUMEN
We study the electronic heat capacity (EHC) and the Pauli spin paramagnetic susceptibility (PSPS) of topological crystalline insulator SnTe (001) thin film in the presence of dilute charged impurities in an effective Hamiltonian model for the low-energy regime such as impurity concentration and impurity scattering potential effects. To calculate the EHC and PSPS using the Boltzmann method, we first calculate the electronic density of states by means of the Green's function approach. Also, the impurity effects are considered with the aid of the T-matrix approximation. We demonstrate that the hybridization potential between the front and back surfaces in SnTe (001) thin films leads to the band gap opening and to the zero PSPS at low temperatures obeying the Fermi liquid theory. In particular, we demonstrate two scenarios including the possibilities of the same and different impurity doping. It is shown that in both cases the midgap states emerge, the cation-anion symmetry breaks down and the Fermi liquid theory loses its validity. Moreover, the critical scattering potential with respect to the hybridization potential is found for the validity limit of the Fermi liquid theory. Finally, the Schottky anomaly and the crossover in EHC and PSPS, respectively, are discussed. Our results have strong implications for applications based on SnTe (001) thin films.
RESUMEN
In this work, the perturbation-induced phase transitions in noncentrosymmetric quantum spin Hall insulators (QSHIs) are analytically addressed. In particular, the dilute charged impurity, the electric field, and the Zeeman splitting field are considered within the tight-binding Hamiltonian model, Green's function approach, and the Born approximation. Following theC3vsymmetry breaking in the PbBiI compound as a representative QSHI, the band gap becomes larger via the electric field, while the system transits to the semimetallic phase via the dilute charged impurities and Zeeman field, modifying the degenerate states in the electronic density of states. While the coexistence of electric field and impurities demonstrate that the system backs to its initial semiconducting phase, the combined Zeeman field and impurities do not alter the robust semimetallic phase.
RESUMEN
Being able to tune the anisotropic interband transitions in phosphorene at finite temperature offers an enormous amount of possibilities in finding new insights in the optoelectronic community. To contribute to this goal we propose a Zeeman spin-splitting field aiming at absorbing various frequencies of the incident light. Employing the tight-binding Hamiltonian to describe the carrier dynamics and the Kubo formalism to formulate the orientation-dependent interband optical conductivity (IOC) and optical activity of phosphorene we investigate the absorption and scattering mechanisms in phosphorene depending on the Zeeman field strength and optical energy parameters. The optical activity features are characterized by exploring the eccentricity and shift phase of reflected and transmitted electromagnetic waves of the incident light. Different electronic phases in the absence and presence of Zeeman field ultimate different types of interband transitions of which in all cases the IOC along the armchair direction is larger than the zigzag one. However, we observed an irregular (regular) process for IOC with the Zeeman field along the armchair (zigzag) direction, resulting in irregular (regular) absorption and scattering mechanisms. Additionally, a little to no effects for temperature-dependent IOC are provided with the Zeeman field in undoped phosphorene. Further, almost linearly and elliptically polarizations are reported for the transmitted and reflected waves, respectively, indicating that the phosphorene is almost transparent. The emergence of Zeeman spin-splitting effects in optoelectronic properties of phosphorene is pleasant to make it a great potential candidate for logic applications.