Edge magnetism impact on electrical conductance and thermoelectric properties of graphenelike nanoribbons

Abstract

Edge states in narrow quasi two-dimensional nanostructures determine, to a large extent, their electric, thermoelectric and magnetic properties. Non-magnetic edge states may quite often lead to topological insulator type behavior. However another scenario develops when the zigzag edges are magnetic and the time reversal symmetry is broken. In this work we report on the electronic band structure modifications, electrical conductance and thermoelectric properties of narrow zigzag nanoribbons with spontaneously magnetized edges. Theoretical studies based on the Kane-Mele- Hubbard tight-binding model show that for silicene, germanene and stanene both the Seebeck coefficient and the thermoelectric power factor are strongly enhanced for energies close to the charge neutrality point. Perpendicular gate voltage lifts the spin degeneracy of energy bands in the ground state with antiparallel magnetized zigzag edges and makes the electrical conductance significantly spin-polarized. Simultaneously the gate voltage worsens the thermoelectric performance. Estimated room-temperature figures of merit for the aforementioned nanoribbons can exceed a value of 3 if phonon thermal conductances are adequately reduced.

6 pages, 8 figures

References in corpus (3)

• Electronic structure of silicon-based nanostructures
• Room temperature magnetic order on zigzag edges of narrow graphene nanoribbons
• Engineering Enhanced Thermoelectric Properties in Zigzag Graphene Nanoribbons

Cited by in corpus (5)

• Second-order topological corner states in zigzag graphene nanoflake with different types of edge magnetic configurations
• Engineering topologically protected zero-dimensional interface end states in antiferromagnetic heterojunction graphene nanoflakes
• Selected graphenelike zigzag nanoribbons with chemically functionalized edges: Implications for electronic and magnetic properties
• Electronic and magnetic properties of silicene monolayer under bi-axial mechanical strain: a first-principles study
• Zigzag nanoribbon of gated bilayer hexagonal crystals with spontaneous edge magnetism