UCL logo

UCL Discovery

UCL home » Library Services » Electronic resources » UCL Discovery

Making tracks: electronic excitation roles in forming swift heavy ion tracks

Itoh, N; Duffy, DM; Khakshouri, S; Stoneham, AM; (2009) Making tracks: electronic excitation roles in forming swift heavy ion tracks. J PHYS-CONDENS MAT , 21 (47) , Article 474205. 10.1088/0953-8984/21/47/474205. Green open access

[img]
Preview
PDF
0953-8984_21_47_474205.pdf

Download (378kB)

Abstract

Swift heavy ions cause material modification along their tracks, changes primarily due to their very dense electronic excitation. The available data for threshold stopping powers indicate two main classes of materials. Group I, with threshold stopping powers above about 10 keV nm(-1), includes some metals, crystalline semiconductors and a few insulators. Group II, with lower thresholds, comprises many insulators, amorphous materials and high T-c oxide superconductors. We show that the systematic differences in behaviour result from different coupling of the dense excited electrons, holes and excitons to atomic (ionic) motions, and the consequent lattice relaxation. The coupling strength of excitons and charge carriers with the lattice is crucial. For group II, the mechanism appears to be the self- trapped exciton model of Itoh and Stoneham ( 1998 Nucl. Instrum. Methods Phys. Res. B 146 362): the local structural changes occur roughly when the exciton concentration exceeds the number of lattice sites. In materials of group I, excitons are not self- trapped and structural change requires excitation of a substantial fraction of bonding electrons, which induces spontaneous lattice expansion within a few hundred femtoseconds, as recently observed by laser- induced time- resolved x- ray diffraction of semiconductors. Our analysis addresses a number of experimental results, such as track morphology, the efficiency of track registration and the ratios of the threshold stopping power of various materials.

Type: Article
Title: Making tracks: electronic excitation roles in forming swift heavy ion tracks
Open access status: An open access version is available from UCL Discovery
DOI: 10.1088/0953-8984/21/47/474205
Publisher version: http://dx.doi.org/10.1088/0953-8984/21/47/474205
Language: English
Additional information: Text made available to UCL Discovery by kind permission of IOP Publishing, 2012
Keywords: SUPERHIGH-ENERGY IONS, NONEQUILIBRIUM ELECTRON, PHASE-TRANSITIONS, DAMAGE CREATION, TIME-DEPENDENCE, SPIKE MECHANISM, MEV FULLERENES, STRUCTURE MAPS, 300 K, METALS
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > London Centre for Nanotechnology
URI: http://discovery.ucl.ac.uk/id/eprint/95943
Downloads since deposit
480Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item