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HL: Fachverband Halbleiterphysik

HL 23: 2D materials: Graphene and BN (joint session HL/DS)

HL 23.3: Vortrag

Dienstag, 13. März 2018, 14:30–14:45, A 151

Magnetic field-induced metal-insulator transition of graphene at filling factor ν=0 — •Sung Ju Hong, Christopher Belke, Johannes C. Rode, Benedikt Brechtken, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover, Hannover, Germany

We have observed magnetic field-induced metal-insulator transition (MIT) at filling factor ν=0 of hexagonal boron nitride (h-BN) encapsulated single-layer graphene. The temperature dependent longitudinal resistance (R_xx) with ν=0 shows MIT at critical magnetic field, B_c≈8T below (above) which metallic (insulating) behavior occurs. In the metallic regime, the negative magnetoresistance appears, which can be explained by counter-propagating opposite-spin polarized edge state [1,2]. In the insulating regime, the divergence of the R_xx was obtained and the resistance showed thermal activation gap behavior. We attribute the MIT with ν=0 to the magnetic field-induced transition from spin polarized state to valley polarized state at B_c.

[1] Peng Wei et al., Nature Mater. 15, 711 (2016).

[2] Javier D. Sanchez-Yamagishi et al., Nature Nanotech. 12, 118 (2017).