Armchair graphene nanoribbons with giant spin thermoelectric efficiency

چکیده مقاله

Spin-caloritronic effects in armchair graphene nanoribbons (AGNRs) with various ribbon widths and
periodic structural defects in the form of triangular antidots were systematically studied. Our results
showed that by engineering defects in AGNRs, one could not only reduce the phononic thermal
conductance for enhancing the thermoelectric efficiency, but also induce a ferromagnetic ground state.
Interestingly, AGNRs with triangular antidots exhibit spin-semiconducting behavior with a tunable spin
gap and a narrow spin-polarized band around the Fermi level. Therefore, AGNRs with antidots exhibit
spin-up and spin-down currents with opposite flow directions under a temperature gradient, and they
also exhibit a giant spin Seebeck coefficient (Ssp ’ 2 mV K1) and spin figure of merit (ZspT ’ 15) that
are much larger than those of zigzag GNRs. Finally, these results pave the way towards the application
of defective AGNRs in spin-caloritronic devices operating at room temperature with a giant spin
thermoelectric efficiency.