title: Two-dimensional mineral [Pb2BiS3][AuTe2]: high-mobility charge carriers in single-atom-thick layers.
abstract: Two-dimensional (2D) electronic systems are of wide interest due to their richness in chemical and physical phenomena and potential for technological applications. Here we report that [Pb2BiS3][AuTe2], known as the naturally occurring mineral buckhornite, hosts 2D carriers in single-atom-thick layers. The structure is composed of stacking layers of weakly coupled [Pb2BiS3] and [AuTe2] sheets. The insulating [Pb2BiS3] sheet inhibits interlayer charge hopping and confines the carriers in the basal plane of the single-atom-thick [AuTe2] layer. Magneto-transport measurements on synthesized samples and theoretical calculations show that [Pb2BiS3][AuTe2] is a multiband semimetal with a compensated density of electrons and holes, which exhibits a high hole carrier mobility of ∼1360 cm(2)/(V s). This material possesses an extremely large anisotropy, Γ = ρ(c)/ρ(ab) ≈ 10(4), comparable to those of the benchmark 2D materials graphite and Bi2Sr2CaCu2O(6+δ). The electronic structure features linear band dispersion at the Fermi level and ultrahigh Fermi velocities of 10(6) m/s, which are virtually identical to those of graphene. The weak interlayer coupling gives rise to the highly cleavable property of the single crystal specimens. Our results provide a novel candidate for a monolayer platform to investigate emerging electronic properties.
authors.affiliation: †Department of Chemistry, ‡Department of Physics and Astronomy, and §Department of Materials Science and Engineering, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Lei
authors.initials: L
authors.lastname: Fang
authors.forename: Jino
authors.initials: J
authors.lastname: Im
authors.forename: Constantinos C
authors.initials: CC
authors.lastname: Stoumpos
authors.forename: Fengyuan
authors.initials: F
authors.lastname: Shi
authors.forename: Vinayak
authors.initials: V
authors.lastname: Dravid
authors.forename: Maxime
authors.initials: M
authors.lastname: Leroux
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Freeman
authors.forename: Wai-Kwong
authors.initials: WK
authors.lastname: Kwok
authors.forename: Duck Young
authors.initials: DY
authors.lastname: Chung
authors.forename: Mercouri
authors.initials: M
authors.lastname: Kanatzidis