Response of Si and InSb to ultrafast laser pulses

Dumitrică, Traian; Burzo, Andrea; Dou, Yusheng; Allen, Roland E.

doi:10.1002/pssb.200404934

Cited by 36 publications

(21 citation statements)

References 44 publications

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“…Finally, an incorporation of the information on the transient changes in the interatomic bonding and thermophysical properties of the target material in the electronically excited state (Stages 1 and 2 in Fig. 3.1), revealed in electronic structure calculations and theoretical analysis, e.g., [23][24][25][26][27][28][29][30][31][32][33][34][35][36][131][132][133], into large-scale atomistic simulations is needed for investigation of the implications of the initial ultrafast atomic dynamics for the final outcome of short-pulse laser irradiation.…”

Section: Discussionmentioning

confidence: 99%

“…The description of the effect of the electronic excitation on the material properties is typically performed by means of computationally expensive electronic structure calculations, e.g., [23][24][25][26][27][28][29][30][31][32][33][34][35][36]. Simulations based on electronic structure calculations provide information on the changes in the interatomic bonding and the ultrafast atomic dynamics induced by the electronic excitation.…”

Section: Introductionmentioning

confidence: 99%

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Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Zhigilei

Lin

Ivanov

et al. 2009

Laser-Surface Interactions for New Materials Production

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Summary. Molecular/atomic-level computer modeling of laser-materials interactions is playing an increasingly important role in the investigation of complex and highly nonequilibrium processes involved in short-pulse laser processing and surface modification. This chapter provides an overview of recent progress in the development of computational methods for simulation of laser interactions with organic materials and metals. The capabilities, advantages, and limitations of the molecular dynamics simulation technique are discussed and illustrated by representative examples. The results obtained in the investigations of the laser-induced generation and accumulation of crystal defects, mechanisms of laser melting, photomechanical effects and spallation, as well as phase explosion and massive material removal from the target (ablation) are outlined and related to the irradiation conditions and properties of the target material. The implications of the computational predictions for practical applications, as well as for the theoretical description of the laser-induced processes are discussed. IntroductionShort-pulse lasers are used in a diverse range of applications, from advanced materials processing, cutting, drilling, and surface micro-and nanostructuring [1,2] to pulsed-laser deposition of thin films and coatings [3], laser surgery [4,5], and artwork restoration [6,7], and to the exploration of the conditions for inertial confinement fusion, with the world's most energetic laser system being built at the National Ignition Facility at Lawrence Livermore National Laboratory [8]. At the fundamental science level, short-pulse laser irradiation has the ability to bring material into a highly nonequilibrium state and provides a unique opportunity to probe the material behavior under extreme conditions. In particular, optical pump-probe experiments have been used to investigate transient changes in the electronic structure of the irradiated surface with high (often subpicosecond) temporal resolution [9][10][11][12][13], whereas recent advances in time-resolved X-ray and electron diffraction

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Zhigilei

Lin

Ivanov

et al. 2009

Laser-Surface Interactions for New Materials Production

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“…The concluded that the phonon squeezing playing the role as the precursor to nonthermal melting with the increasing of laser fluence. Threshold intensities of nonthermal phase transition for semiconductors (such as, Si and InSb) were reported by utilizing the semiclassical electron-radiation-ion dynamics (SERID) [17]. In this work, the ab initio molecular dynamics simulation method based on finite temperature (FT-DFT) is used to simulate femtosecond laser interaction of germanium.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond laser processing of germanium: anab initiomolecular dynamics study

Ji¹,

Zhang²

2013

J. Phys. D: Appl. Phys.

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An ab initio molecular dynamics study of femtosecond laser processing of germanium is presented in this paper. The method based on the finite temperature density functional theory is adopted to probe the structural change, thermal motion of the atoms, dynamic property of the velocity autocorrelation, and the vibrational density of states. Starting from a cubic system at room temperature (300 ‫)ܭ‬ containing 64 germanium atoms with an ordered arrangement of 1.132 ݊݉ in each dimension, the femtosecond laser processing is simulated by imposing the Nose Hoover thermostat to the electronic subsystem lasting for ~100 ‫ݏ݂‬ and continuing with microcanonical ensemble simulation of ~200 ‫.ݏ݂‬ The simulation results show solid, liquid and gas phases of germanium under adjusted intensities of the femtosecond laser irradiation. We find the irradiated germanium distinguishes from the usual germanium crystal by analyzing their melting and dynamic properties.

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“…Theoretical, experimental, and simulation studies of these systems indicate that extreme carrier densities destabilize the crystal structure and lead to nonthermal melting [3,[5][6][7][8][9][10][11][12][13][14][15][16][17]. Theoretical studies predict a rapid reduction in the shear restoring force when the excited carrier density exceeds a few percent of the valence band electron density [5][6][7].…”

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confidence: 99%

Carrier-Density-Dependent Lattice Stability in InSb

et al. 2007

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The ultrafast decay of the x-ray diffraction intensity following laser excitation of an InSb crystal has been utilized to observe carrier dependent changes in the potential energy surface. For the first time, an abrupt carrier dependent onset for potential energy surface softening and the appearance of accelerated atomic disordering for a very high average carrier density have been observed. Inertial dynamics dominate the early stages of crystal disordering for a wide range of carrier densities between the onset of crystal softening and the appearance of accelerated atomic disordering. DOI: 10.1103/PhysRevLett.98.125501 PACS numbers: 63.20.Kr, 61.10.ÿi, 64.70.Dv, 78.47.+p First-order phase transitions and chemical reactions require crossing a transition state on the potential energy surface (PES). Characterizing the topography of the energy landscape in the vicinity of the transition state represents the key step to understanding the pathway followed during a chemical reaction or first-order phase transition. The experimental and theoretical characterization of these far from equilibrium regions of the PES has proven to be very difficult because of the vanishingly short time spent near the transition state and the multitude of degrees of freedom that influence chemical and physical transformations in the condensed phase. Time-resolved x-ray scattering experiments provide a window for observing the structural dynamics that occur during certain physical transformations. This is achieved by using femtosecond (fs) x-ray pulses to monitor laser initiated dynamics, selectively track the time-dependent evolution of nonequilibrium atomic structures, and extract the shape of a photoinduced PES [1][2][3][4].This approach has proven crucial to investigating the influence of carrier excitation on the stability of tetrahedrally bonded semiconductors. Theoretical, experimental, and simulation studies of these systems indicate that extreme carrier densities destabilize the crystal structure and lead to nonthermal melting [3,[5][6][7][8][9][10][11][12][13][14][15][16][17]. Theoretical studies predict a rapid reduction in the shear restoring force when the excited carrier density exceeds a few percent of the valence band electron density [5][6][7]. A further doubling of the carrier density eliminates the shear restoring force, transforms the room temperature potential energy minimum into a saddle point, and leads to accelerated atomic disordering.The initial ultrafast x-ray diffraction studies of laserexcited InSb at the Sub-Picosecond Pulse Source (SPPS) determined that inertial atomic displacements on a lasersoftened potential energy surface dominate the response to intense optical excitation during the first 500 fs for a range of laser fluences [3]. This predominance of inertial dynamics in a wide fluence range had not been predicted by either theory or simulation. While the studies of Lindenberg et al. [3] and Gaffney et al. [15] covered the mean carrier density range over which theory predicted crystal stability to r...

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Response of Si and InSb to ultrafast laser pulses

Cited by 36 publications

References 44 publications

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Atomic/Molecular-Level Simulations of Laser–Materials Interactions

Femtosecond laser processing of germanium: anab initiomolecular dynamics study

Carrier-Density-Dependent Lattice Stability in InSb

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