ABC-stacked trilayer graphene has exhibited a variety of correlated phenomena owing to its relatively flat bands and gate-tunable bandgap.However,convenient methods are still lacking for identifying ABC graphene with ...ABC-stacked trilayer graphene has exhibited a variety of correlated phenomena owing to its relatively flat bands and gate-tunable bandgap.However,convenient methods are still lacking for identifying ABC graphene with nanometer-scale resolution.Here we demonstrate that the scanning near-field optical microscope working in ambient conditions can provide quick recognition of ABC trilayer graphene with no ambiguity and excellent resolution(∼20 nm).The recognition is based on the difference in their near-field infrared(IR)responses between the ABA and ABC trilayers.We show that in most frequencies,the response of the ABC trilayer is weaker than the ABA trilayer.However,near the graphene phonon frequency(∼1585 cm−1),ABC’s response increases dramatically when gated and exhibits a narrow and sharp Fano-shape resonant line,whereas the ABA trilayer is largely featherless.Consequently,the IR contrast between ABC and ABA becomes reversed and can even be striking(ABC/ABA∼3)near the graphene phonon frequency.The observed near-field IR features can serve as a golden rule to quickly distinguish ABA and ABC trilayers with no ambiguity,which could largely advance the exploration of correlation physics in ABC-stacked trilayer graphene.展开更多
基金supported by the Open Research Fund of Songshan Lake Materials Laboratory(No.2021SLABFK07)the National Key R&D Program of China(No.2021YFA1202902)+2 种基金the National Natural Science Foundation of China(No.12074244)Z S acknowledges support from SJTU(21X010200846)additional support from a Shanghai talent program.
文摘ABC-stacked trilayer graphene has exhibited a variety of correlated phenomena owing to its relatively flat bands and gate-tunable bandgap.However,convenient methods are still lacking for identifying ABC graphene with nanometer-scale resolution.Here we demonstrate that the scanning near-field optical microscope working in ambient conditions can provide quick recognition of ABC trilayer graphene with no ambiguity and excellent resolution(∼20 nm).The recognition is based on the difference in their near-field infrared(IR)responses between the ABA and ABC trilayers.We show that in most frequencies,the response of the ABC trilayer is weaker than the ABA trilayer.However,near the graphene phonon frequency(∼1585 cm−1),ABC’s response increases dramatically when gated and exhibits a narrow and sharp Fano-shape resonant line,whereas the ABA trilayer is largely featherless.Consequently,the IR contrast between ABC and ABA becomes reversed and can even be striking(ABC/ABA∼3)near the graphene phonon frequency.The observed near-field IR features can serve as a golden rule to quickly distinguish ABA and ABC trilayers with no ambiguity,which could largely advance the exploration of correlation physics in ABC-stacked trilayer graphene.
