Effects of model approximations for electron, hole, and photon transport in swift heavy ion tracks

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:388

Article

Rymzhanov, R. A.¹  Medvedev, N. A.^2,3  Volkov, A. E.^1,4,5,6,7 

[1] Joint Inst Nucl Res, Joliot Curie 6, Dubna 141980, Moscow Region, Russia

[2] Czech Acad Sci, Inst Phys, Dept Radiat & Chem Phys, Slovance 2, Prague 18221 8, Czech Republic

[3] Czech Acad Sci, Inst Plasma Phys, Laser Plasma Dept, Slovankou 3, Prague 18200 8, Czech Republic

[4] Natl Res Ctr, Kurchatov Inst, Kurchatov Sq 1, Moscow 123182, Russia

[5] Russian Acad Sci, Lebedev Phys Inst, Leninskij Pr 53, Moscow 119991, Russia

[6] Natl Univ Sci & Technol MISiS, Leninskij Pr 4, Moscow 119049, Russia

[7] Natl Res Nucl Univ MEPhI, Kashirskoye Sh 31, Moscow 115409, Russia

关键词: Swift heavy ion;    Electronic stopping;    TREKIS;    Monte Carlo;    Electronic kinetics;    Photon transport;   

DOI  :  10.1016/j.nimb.2016.11.002

来源: Elsevier

【 摘 要 】

The event-by-event Monte Carlo code, TREKIS, was recently developed to describe excitation of the electron subsystems of solids in the nanometric vicinity of a trajectory of a nonrelativistic swift heavy ion (SHI) decelerated in the electronic stopping regime. The complex dielectric function (CDF) formalism was applied in the used cross sections to account for collective response of a matter to excitation. Using this model we investigate effects of the basic assumptions on the modeled kinetics of the electronic subsystem which ultimately determine parameters of an excited material in an SHI track. In particular, (a) effects of different momentum dependencies of the CDF on scattering of projectiles on the electron subsystem are investigated. The 'effective one-band' approximation for target electrons produces good coincidence of the calculated electron mean free paths with those obtained in experiments in metals. (b) Effects of collective response of a lattice appeared to dominate in randomization of electron motion. We study how sensitive these effects are to the target temperature. We also compare results of applications of different model forms of (quasi-) elastic cross sections in simulations of the ion track kinetics, e.g. those calculated taking into account optical phonons in the CDF form vs. Mott's atomic cross sections. (c) It is demonstrated that the kinetics of valence holes significantly affects redistribution of the excess electronic energy in the vicinity of an SHI trajectory as well as its conversion into lattice excitation in dielectrics and semiconductors. (d) It is also shown that induced transport of photons originated from radiative decay of core holes brings the excess energy faster and farther away from the track core, however, the amount of this energy is relatively small. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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