Structural and electronic properties of realistic two-dimensional amorphous topological insulators

Abstract

We investigate the structure and electronic spectra properties of two-dimensional amorphous bismuthene structures and show that these systems are topological insulators. We employ a realistic modeling of amorphous geometries together with density functional theory for electronic structure calculations. We investigate the system topological properties throughout the amorphization process and find that the robustness of the topological phase is associated with the spin-orbit coupling strength and size of the pristine topological gap. Using recursive non-equilibrium Green's function, we study the electronic transport properties of nanoribbons devices with lengths comparable to experimentally synthesized materials. We find a 2e 2 /h conductance plateau within the topological gap and an onset of Anderson localization at the trivial insulator phase.

Symmetry-Protected Topological Phases in a Rydberg Glass

“…Amorphous solids play an important role in condensed matter physics [1]. In the context of topological physics, while topological phases are primarily pursued in crystalline materials with translational symmetry [2][3][4][5][6][7], recent studies showed that topological phases for noninteracting quantum particles can also exist in two or three dimensional amorphous systems [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. From another perspective, amorphous materials can be viewed as a limiting case when structural disorder arising from atom position randomness is included in a crystalline system.…”

Structural Disorder Induced Second-order Topological Insulators in Three Dimensions

“…Since atoms in amorphous materials are randomly distributed in space, the solids do not respect translational symmetries. While the physics on topological phases of matter is mainly established in crystalline solids with spatial order, it was surprisingly found that topological states can also occur in amorphous solids [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20]. Recently, topological phases have been generalized to the higher-order case where (n−m)-dimensional (with 1 < m ≤ n) gapless boundary states happen in an ndimensional system [21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37].…”