Intercalation experiments on epitaxial graphene are attracting a lot of attention at present as a tool to further boost the electronic properties of 2D graphene. In this work, we studied the intercalation of Pb using buffer layers on 6H-SiC(0001) by means of electron diffraction, scanning tunneling microscopy, photoelectron spectroscopy and in situ surface transport. Large-area intercalation of a few Pb monolayers succeeded via surface defects. The intercalated Pb forms a characteristic striped phase and leads to formation of almost charge neutral graphene in proximity to a Pb layer. The Pb intercalated layer consists of 2 ML and shows a strong structural corrugation. The epitaxial heterostructure provides an extremely high conductivity of σ=100 mS/□. However, at low temperatures (70 K), we found a metal-insulator transition that we assign to the formation of minigaps in epitaxial graphene, possibly induced by a static distortion of graphene following the corrugation of the interface layer.

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Protected and spin-polarized transport channels are the hallmark of topological insulators, coming along with an intrinsic strong spin−orbit coupling. Here we identified such corresponding chiral states in epitaxially grown zigzag graphene nanoribbons (zz-GNRs), albeit with an extremely weak spin−orbit interaction. While the bulk of the monolayer zz-GNR is fully suspended across a SiC facet, the lower edge merges into the SiC(0001) substrate and reveals a surface state at the Fermi energy, which is extended along the edge and splits in energy toward the bulk. All of the spectroscopic details are precisely described within a tight binding model incorporating a Haldane term and strain effects. The concomitant breaking of time-reversal symmetry without the application of external magnetic fields is supported by ballistic transport revealing a conduction of G = e 2 /h.

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High mass loading asymmetric micro-supercapacitors (MSCs) are key components for the development of high-performance energy and power supply systems. Here, a concept for achieving high mass loading electrodes is presented and applied to high mass loading micro-supercapacitors with ultrahigh areal energy and power density. The positive electrode is made from porous carbon with birnessite coverage and multiwalled carbon nanotubes (CNTs) as conducting additives (PIC-CNTs-MnO 2 ). The negative electrode is prepared from hierarchically porous active carbon mixed with CNTs (PICK-CNTs). Both positive and negative electrode materials are tailored to ensure a high content of macro-and mesopores. MSCs with an optimized mass loading of 13.9 mg•cm −2 (maximum: 23.6 mg•cm −2 ) provide an ultrahigh areal capacitance of 1.13 F•cm −2 (volumetric capacitance: 22.6 F•cm −3 ), an outstanding energy of 627.8 μWh•cm −2 , and a maximum power density of 64 mW•cm −2 . About 85% of the initial capacitance remained after 5000 cycles. Moreover, shunt and tandem device testing confirmed a high uniformity of these MSCs, meeting the requirements of adjustable output currents and voltages in microchips.