Magnetic Properties Of Zigzag Graphene Nanoribbons Research Articles

Pauli susceptibility of zigzag graphene nanoribbons

Based on the tight-binding model, we present the analytical expressions for the energy spectrum and Pauli susceptibility of zigzag graphene nanoribbons (ZGNRs). The influences of lattice site, temperature, and ribbon width on the Pauli susceptibility are discussed in detail. The results show that the Pauli susceptibility damps rapidly from the edge to bulk sites at a given finite temperature. In the low-temperature regime, the Pauli susceptibility exhibits a remarkable Curie-law-like behavior, while in the high-temperature regime it displays a normal paramagnetic behavior. As the ribbon width is increased, the Pauli susceptibility at each edge of a given ZGNR gradually increases to a saturated value. These novel magnetic properties of ZGNRs are closely related to edge states.

Realizing semiconductor-half-metal transition in zigzag graphene nanoribbons supported on hybrid fluorographene-graphane nanoribbons.

Hydrogenation and fluorination provide promising applications for tuning the properties of graphene-based nanomaterials. Using first-principles calculations, we investigate the electronic and magnetic properties of zigzag graphene nanoribbons (ZGNRs) supported on hydrogenated and fluorinated ZGNRs. Our results indicate that the support of zigzag graphane nanoribbon with its full width has less impact on the electronic and magnetic properties of ZGNRs, whereas the ZGNRs supported on fluorographene nanoribbons can be tuned to metal with almost degenerated ferro- and anti-ferromagnetic states due to the intrinsic polarization of substrate. The ZGNRs supported on zigzag hybrid fluorographene-graphane nanoribbons are spin-polarized half-semiconductors with distinct band gaps for spin-up and spin-down channels. Interestingly, in the absence of an external electric field, the spin-polarized band gaps of supported ZGNRs can be well modulated in the opposite direction by changing the ratio of fluorination to hydrogenation concentration in hybrid substrates. Furthermore, the ZGNRs supported on hybrid nanoribbons exhibit the half-semiconducting to half-metallic behavior transition as the interlayer spacing is gradually reduced, which is realized more easily for the hybrid support with a relatively wide fluorographene moiety compared to its narrow counterpart. Present results provide a novel way for designing substrate-supported graphene spintronic devices.

ON THE ROBUSTNESS OF MAGNETISM IN ZIGZAG GRAPHENE NANORIBBONS

In this work, using the single-band Hubbard model, we numerically study the magnetic ordering in zigzag graphene nanoribbons (ZGNRs). We calculate density of states and charge density distribution in the ZGNR, and show the nontrivial behavior of its electronic band structure in the presence of an external transverse electric field. Then, the robustness of such edge magnetic ordering and consequent half-metallicity is investigated for nanoribbons defected with single-atom vacancies. Our results show that the nontrivial magnetic properties of ZGNRs are robust to an acceptable percentage of single atom vacancies.

Tuning electronic and magnetic properties of zigzag graphene nanoribbons by large-scale bending

Using density-functional theory calculations, we show that the electronic and magnetic properties of zigzag graphene nanoribbons (ZGNRs) are highly sensitive to large scale curvature. As the curvature increases, the system experiences a transformation from the antiferromagnetic state to a nonmagnetic state and then back to the antiferromagnetic state. The energy gap first remains almost invariant and then decreases monotonically. The results demonstrate a facile strategy to tune the electronic and magnetic properties of ZGNRs, and furthermore provide an avenue to design versatile electronic and spin devices.