2018/09/11 by Zahra Aslani, Esmaeil Taghizadeh Sisakht, Farhad Fazileh +2 · 6 citations
Materials Science · Mathematics · Physics and Astronomy · #2D Materials and Applications #Ab initio #Condensed matter physics #Conductance #Graphene research and applications #Hamiltonian (control theory) #Magnetic field #Materials science #Mathematics #Monolayer #Nanotechnology #Phase transition #Physics #Quantum mechanics #Quantum phase transition #Topological Materials and Phenomena #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.99.115421
published in Physical review. B./Physical review. B 99(11) (American Physical Society) · 8 pages, 6 figures
arxiv created 2018/09/11 · openalex created_date 2018/09/27 · openalex publication_date 2019/03/15 · arxiv updated 2019/03/27 · openalex updated_date 2026/08/05
An effective tight-binding (TB) Hamiltonian for monolayer GeSnH2 is constructed which has an inversion-asymmetric honeycomb structure. The low-energy band structure of our TB model agrees very well with previous ab initio calculations even under biaxial tensile strain. Our model predicts a phase transition at 7.5% biaxial tensile strain in agreement with DFT calculations. Upon 8.5% strain the system exhibits a band gap of 134 meV, suitable for room temperature applications. It is shown that an external applied magnetic field produces a special phase which is a combination of the quantum Hall (QH) and quantum spin Hall (QSH) phases; and at a critical magnetic field strength the QSH phase completely disappears. The topological nature of the phase transition is confirmed from: (1) the calculation of the ℤ2 topological invariant, and (2) quantum transport properties of disordered GeSnH2 nanoribbons which allows us to determine the universality class of the conductance fluctuations. The application of an external applied magnetic field reduces the conductance fluctuations by a factor of √(2).