Transport across a topoelectrical Weyl semimetal heterojunction
We propose a general method to realize and calculate the transmission in a Weyl semimetal (WSM) heterostructure by employing a periodic three-dimensional topoelectrical (TE) circuit network. By drawing the analogy between inductor-capacitor circuit lattices and quantum mechanical tight-binding (TB) models, we show that the energy flux in a TE network is analogous to the probability flux in a TB Hamiltonian. TE systems offer a key advantage in that they can be easily tuned to achieve different topological WSM phases simply by varying the capacitances and inductances. The above analogy opens the way to the study of tunneling across heterojunctions separating different types of WSMs in TE circuits, a situation which is virtually impossible to realize in physical WSM materials. We show that the energy flux transmission in a WSM heterostructure depends highly on the relative orientation of the transport direction and the $k$-space tilt direction. For the transmission from a Type I WSM source lead to a Type II WSM drain lead, all valleys transmit equally when the tilt and transmission directions are perpendicular to each other. In contrast, large inter-valley scattering is required for transmission when the tilt and transport directions are parallel to each other, leading to valley-dependent transmission. We describe a Type III WSM phase intermediate between the Type I and Type II phases. An `anti-Klein' tunneling occurs between a Type I source and Type III drain where the transmission is totally suppressed for some valleys at normal incidence. This is in direct contrast to the usual Klein tunneling in Dirac materials where normally incident flux is perfectly transmitted. Owing to the ease of fabrication and experimental accessibility, TE circuits offer an excellent testbed to study the extraordinary transport phenomena in WSM based heterostructures.