Robust non-integer conductance in disordered 2D Dirac semimetals

Abstract

We study the conductance $G$ of 2D Dirac semimetal nanowires at the presence of disorder. For an even nanowire length $L$ determined by the number of unit cells, we find non-integer values for $G$ that are independent of $L$ and persist with weak disorder, indicated by the vanishing fluctuations of $G$. The effect is created by a combination of the scattering effects at the contacts(interface) between the leads and the nanowire, an energy gap present in the nanowire for even $L$ and the topological properties of the 2D Dirac semimetals. Unlike conventional materials the reduced $G$ due to the scattering at the interface, is stabilized at non-integer values inside the nanowire, leading to a topological phase for weak disorder. For strong disorder the system leaves the topological phase and the fluctuations of $G$ are increased as the system undergoes a transition/crossover toward the Anderson localized(insulating) phase, via a non-standard disordered phase. We study the scaling and the statistics of $G$ at these phases. In addition we have found that the effect of robust non-integer $G$ disappears for odd $L$, which results in integer $G$, determined by the number of open channels in the nanowire, due to resonant scattering.

arXiv comment8 pages, 10 figures, some revisions along with an expanded analysis including new figures, published in Journal of Physics: Condensed Matter

References in corpus (23)

• Quantum Spin Hall Effect in Graphene
• Unpaired Majorana fermions in quantum wires
• Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi
• Experimental Realization of a Three-Dimensional Dirac Semimetal
• Dirac Semimetals in Two Dimensions
• Hourglass Fermions
• Effect of Disorder on Transport in Graphene
• The recursive Green's function method for graphene
• Subtle leakage of a Majorana mode into a quantum dot
• Experimental Discovery of the First Nonsymmorphic Topological Insulator KHgSb
• Prediction of two-dimensional nodal-line semimetal in a carbon nitride covalent network
• Graphene via large N I: Renormalization
• Topological Insulators from Group Cohomology
• Anderson localization and the quantum phase diagram of three dimensional disordered Dirac semimetals
• Two-dimensional honeycomb borophene oxide: Strong anisotropy and nodal loop transformation
• Diffusive Quantum Criticality in Three Dimensional Disordered Dirac Semimetals
• Fractional Quantum Hall Effect in Weyl Semimetals
• Experimental Realization of Two-Dimensional Buckled Lieb lattice
• Conductance fluctuations in disordered 2D topological insulator wires: From quantum spin-Hall to ordinary quantum phases
• Edge states versus diffusion in disordered graphene flakes
• Edge states in a two-dimensional non-symmorphic semimetal
• Coherent wave transmission in quasi-one-dimensional systems with Lévy disorder
• Geometrical spin manipulation in Dirac flakes