title: Anisotropic in-plane thermal conductivity of black phosphorus nanoribbons at temperatures higher than 100 K.
abstract: Black phosphorus attracts enormous attention as a promising layered material for electronic, optoelectronic and thermoelectric applications. Here we report large anisotropy in in-plane thermal conductivity of single-crystal black phosphorus nanoribbons along the zigzag and armchair lattice directions at variable temperatures. Thermal conductivity measurements were carried out under the condition of steady-state longitudinal heat flow using suspended-pad micro-devices. We discovered increasing thermal conductivity anisotropy, up to a factor of two, with temperatures above 100 K. A size effect in thermal conductivity was also observed in which thinner nanoribbons show lower thermal conductivity. Analysed with the relaxation time approximation model using phonon dispersions obtained based on density function perturbation theory, the high anisotropy is attributed mainly to direction-dependent phonon dispersion and partially to phonon-phonon scattering. Our results revealing the intrinsic, orientation-dependent thermal conductivity of black phosphorus are useful for designing devices, as well as understanding fundamental physical properties of layered materials.
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Sangwook
authors.initials: S
authors.lastname: Lee
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Joonki
authors.initials: J
authors.lastname: Suh
authors.affiliation: School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Sijie
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Yeonbae
authors.initials: Y
authors.lastname: Lee
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Guo
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Hwan
authors.initials: H
authors.lastname: Sung Choe
authors.affiliation: School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Aslihan
authors.initials: A
authors.lastname: Suslu
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Yabin
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.
authors.forename: Changhyun
authors.initials: C
authors.lastname: Ko
authors.affiliation: Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Joonsuk
authors.initials: J
authors.lastname: Park
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: Jingbo
authors.initials: J
authors.lastname: Li
authors.affiliation: Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), 3 Research Link, Singapore 117602, Singapore.
authors.forename: Kedar
authors.initials: K
authors.lastname: Hippalgaonkar
authors.affiliation: Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jeffrey J
authors.initials: JJ
authors.lastname: Urban
authors.affiliation: School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona 85287, USA.
authors.forename: Sefaattin
authors.initials: S
authors.lastname: Tongay
authors.affiliation: Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Junqiao
authors.initials: J
authors.lastname: Wu