Manipulating topological inner-edge states in hybrid silicene nanoribbons

Edge states in quantum spin Hall insulators have important applications in low-dissipation devices. However, the breaking of the valley degree of freedom for finite-sized nanoribbons violates the formation of gapless valley edge states. In this work, we investigate the topological and transport properties in a hybrid silicene nanoribbon, two halves of which are in different topological phases modulated by external perpendicular electric fields and antiferromagnetic exchange fields independently. By observing the inner-edge states, different band insulators, especially the quantum spin and valley Hall insulators, can be distinguished. Special inner-edge states, such as single valley or spin-valley channels, cause the valley thermal rectification effect, which can be used to design topological thermal diodes. Furthermore, we calculate the thermoelectric performance of inner-edge states with a dual scattering time model and find an enhancement compared with the original topological edge states at a higher temperature. These spin-and valley-resolved inner-edge states may facilitate more applications in topological valley electronics and thermoelectronics.