2,959 research outputs found
The edge engineering of topological Bi(111) bilayer
A topological insulator is a novel quantum state, characterized by
symmetry-protected non-trivial edge/surface states. Our first-principle
simulations show the significant effects of the chemical decoration on edge
states of topological Bi(111) bilayer nanoribbon, which remove the trivial edge
state and recover the Dirac linear dispersion of topological edge state. By
comparing the edge states with and without chemical decoration, the Bi(111)
bilayer nanoribbon offers a simple system for assessing conductance fluctuation
of edge states. The chemical decoration can also modify the penetration depth
and the spin texture of edge states. A low-energy effective model is proposed
to explain the distinctive spin texture of Bi(111) bilayer nanoribbon, which
breaks the spin-momentum orthogonality along the armchair edge.Comment: 5 pages, 5 figure
Geometric curvatures of plane symmetry black hole
In this paper, we study the properties and thermodynamic stability of the
plane symmetry black hole from the viewpoint of geometry. Weinhold metric and
Ruppeiner metric are obtained, respectively. The Weinhold curvature gives phase
transition points, which correspond to the first-order phase transition only at
N=1, where is a parameter in the plane symmetry black hole. While the
Ruppeiner one shows first-order phase transition points for arbitrary . Both of which give no any information about the second-order phase
transition. Considering the Legendre invariant proposed by Quevedo et. al., we
obtain a unified geometry metric, which gives a correctly the behavior of the
thermodynamic interactions and phase transitions. The geometry is also found to
be curved and the scalar curvature goes to negative infinity at the Davies'
phase transition points when the logarithmic correction is included.Comment: 16 pages, 6 figure
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