title: Pressure-Induced Amorphization and a New High Density Amorphous Metallic Phase in Matrix-Free Ge Nanoparticles.
abstract: Over the last two decades, it has been demonstrated that size effects have significant consequences for the atomic arrangements and phase behavior of matter under extreme pressure. Furthermore, it has been shown that an understanding of how size affects critical pressure-temperature conditions provides vital guidance in the search for materials with novel properties. Here, we report on the remarkable behavior of small (under ~5 nm) matrix-free Ge nanoparticles under hydrostatic compression that is drastically different from both larger nanoparticles and bulk Ge. We discover that the application of pressure drives surface-induced amorphization leading to Ge-Ge bond overcompression and eventually to a polyamorphic semiconductor-to-metal transformation. A combination of spectroscopic techniques together with ab initio simulations were employed to reveal the details of the transformation mechanism into a new high density phase-amorphous metallic Ge.
authors.affiliation: Department of Physics, Blackett Laboratory, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Niccolo R C
authors.initials: NR
authors.lastname: Corsini
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Yuanpeng
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom.
authors.forename: William R
authors.initials: WR
authors.lastname: Little
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom.|Electrical and Electronics Engineering, Yildirim Campus, Bursa Orhangazi University , 16245 Yildirim, Bursa, Turkey.
authors.forename: Ali
authors.initials: A
authors.lastname: Karatutlu
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Osman
authors.initials: O
authors.lastname: Ersoy
authors.affiliation: Department of Physics, Blackett Laboratory, Imperial College London , Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Peter D
authors.initials: PD
authors.lastname: Haynes
authors.affiliation: Department of Physics, King's College London , Strand, London WC2R 2LS, United Kingdom.
authors.forename: Carla
authors.initials: C
authors.lastname: Molteni
authors.affiliation: TCM Group, Cavendish Laboratory, University of Cambridge , JJ Thomson Avenue, Cambridge CB3 0HE, United Kingdom.|Department of Physics, University of Warwick , Coventry CV4 7AL, United Kingdom.
authors.forename: Nicholas D M
authors.initials: ND
authors.lastname: Hine
authors.affiliation: Malta Consolider Team, Departmento CITIMAC, Universidad de Cantabria , Avenida Los Castros s/n, 39005 Santander, Spain.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Hernandez
authors.affiliation: Malta Consolider Team, Departmento CITIMAC, Universidad de Cantabria , Avenida Los Castros s/n, 39005 Santander, Spain.
authors.forename: Jesus
authors.initials: J
authors.lastname: Gonzalez
authors.affiliation: Malta Consolider Team, Departmento CITIMAC, Universidad de Cantabria , Avenida Los Castros s/n, 39005 Santander, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Rodriguez
authors.affiliation: High Pressure Physics Institute, RAS , 142190 Troitsk, Moscow Region, Russia.
authors.forename: Vadim V
authors.initials: VV
authors.lastname: Brazhkin
authors.affiliation: School of Physics and Astronomy, Queen Mary University of London , Mile End Road, London E1 4NS, United Kingdom.
authors.forename: Andrei
authors.initials: A
authors.lastname: Sapelkin
keywords: Ge nanoparticles; Raman; X-ray absorption; amorphization; density functional theory calculations; high pressure; phase transformation