It is supposed the existence of a curved graphene sheet with the geometry of a Bour surface $B_{ n}$, such as the catenoid (or helicoid), $B_{ 0}$, and the classical Enneper surface, $B_{ 2}$, among others. In particular, in this work, the propagation of the electronic degrees of freedom on these surfaces is studied based on the Dirac equation. As a consequence of the polar geometry of $B_{ n}$, it is found that the geometry of the surface causes the Dirac fermions to move as if they would be subjected to an external potential coupled to a spin-orbit term. The geometry-induced potential is interpreted as a barrier potential, which is asymptotically zero. Furthermore, the behaviour of asymptotic Dirac states and scattering states are studied through the Lippmann-Schwinger formalism. It is found that for surfaces $B_{ 0}$ and $B_{ 1}$, the total transmission phenomenon is found for sufficiently large values of energy, while for surfaces $B_{ n}$, with $n\geq 2$, it is shown that there is an energy point $E_{ K}$ where Klein's paradox is realized, while for energy values $E\gg E_{ K}$ it is found that the conductance of the hypothetical material is completely suppressed, $\mathcal{ G}(E)\to 0$.
Categories: cond-mat.mes-hall cond-mat.mtrl-sci math-ph math.MP