Growth, surface morphology, and electrical resistivity of fully strained substoichiometric epitaxial TiNx (0.67⩽x&amp;lt;1.0) layers on MgO(001)

Shin, Cheung Soo; Rudenja, S.; Gall, Daniel; Hellgren, Niklas; Lee, T.-Y.; Petrov, I.; Greene, J. E.

doi:10.1063/1.1629155

Cited by 124 publications

(75 citation statements)

References 34 publications

(14 reference statements)

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“…Simulation supercells contain 215 atoms (3 × 3 × 3 TiN conventional B1 unit cells with one Ti vacancy). We notice that TiN is an electrical conductor [89]. This implies long correlation lengths in the electronic structure of the system.…”

Section: B Aimd and Ne-aimd Simulationsmentioning

confidence: 99%

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

et al. 2017

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We use the color diffusion (CD) algorithm in nonequilibrium (accelerated) ab initio molecular dynamics simulations to determine Ti monovacancy jump frequencies in NaCl-structure titanium nitride (TiN), at temperatures ranging from 2200 to 3000 K. Our results show that the CD method extended beyond the linear-fitting rate-versus-force regime [Sangiovanni et al., Phys. Rev. B 93, 094305 (2016)] can efficiently determine metal vacancy migration rates in TiN, despite the low mobilities of lattice defects in this type of ceramic compound. We propose a computational method based on gamma-distribution statistics, which provides unambiguous definition of nonequilibrium and equilibrium (extrapolated) vacancy jump rates with corresponding statistical uncertainties. The acceleration-factor achieved in our implementation of nonequilibrium molecular dynamics increases dramatically for decreasing temperatures from 500 for T close to the melting point T m , up to 33 000 for T ≈ 0.7 T m .

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Section: B Aimd and Ne-aimd Simulationsmentioning

confidence: 99%

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

et al. 2017

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“…Due to remarkable physical properties including high hardness and mechanical strength [1][2][3], chemical inertness [4][5][6], thermal stability [7], and electrical conductivity which varies from metallic to semiconducting [8][9][10], transition-metal (TM) nitride thin films are used in a wide range of applications: from wear-resistant protective coatings for cutting tools and engine components [11; 12] to diffusion barriers in electronic devices [13]. The actual properties achieved by a given TM nitride film depend in large part on surface and microstructural evolution during reactive growth.…”

Section: Introductionmentioning

confidence: 99%

Ab initio and classical molecular dynamics simulations of N2 desorption from TiN(001) surfaces

et al. 2014

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Ab-initio molecular dynamics (AIMD) simulations based on density functional theory show that N adatoms are chemisorbed in threefold sites close to a N surface atom and between the two diagonally-opposed neighboring Ti surface atoms on TiN(001). The most probable N adatom reaction pathway, even in the presence of nearby N adatoms, is for the N adatom and N surface atom pair to first undergo several exchange reactions and then desorb as a N2 molecule, resulting in a surface anion vacancy, with an activation barrier Edes of 1.37 eV and an attempt frequency Ades = 3.4x10 13 s -1 . Edes is essentially equal to the N adatom surface diffusion barrier, Es = 1.39 eV, whileAs is only three to four times larger than Ades, indicating that isolated N adatoms migrate for only short distances prior to N2 desorption. The probability of N2 desorption via recombination of N adatoms on TiN(001) is much lower due to repulsive adatom/adatom interactions at separations less than ~3 Å which rapidly increase to ~2 eV at a separation of 1.5 Å. We obtain good qualitative and quantitative agreement with the above results using the modified embedded atom method (MEAM) potential to perform classical molecular dynamics (CMD) simulations.

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“…Over the past two decades, a major quest in materials science has been the development of artificial materials with increasing hardness. Successful examples include phase-stability tuning, 1 superhardening of refractory nitrides via the development of artificial superlattices, 2, 3 nano-scale composites, 4, 5 vacancy-induced hardening, [6][7][8][9] and polytype-mixtures in transition-metal carbides and nitrides. 10 However, each of these hardening mechanisms extracts a steep price in terms of increased brittleness.…”

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confidence: 99%

Toughness enhancement in hard ceramic thin films by alloy design

Kindlund¹,

Sangiovanni²,

et al. 2013

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Hardness is an essential property for a wide range of applications. However, hardness alone, typically accompanied by brittleness, is not sufficient to prevent failure in ceramic films exposed to high stresses. Using VN as a model system, we demonstrate with experiment and density functional theory (DFT) that refractory VMoN alloys exhibit not only enhanced hardness, but dramatically increased ductility. V0.5Mo0.5N hardness is 25% higher than that of VN. In addition, while nanoindented VN, as well as TiN reference samples, suffer from severe cracking typical of brittle ceramics, V0.5Mo0.5N films do not crack. Instead, they exhibit material pile-up around nanoindents, characteristic of plastic flow in ductile materials. Moreover, the wear resistance of V0.5Mo0.5N is considerably higher than that of VN. DFT results show that tuning the occupancy of d–t2g metallic bonding states in VMoN facilitates dislocation glide, and hence enhances toughness, via the formation of stronger metal/metal bonds along the slip direction and weaker metal/N bonds across the slip plane

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Growth, surface morphology, and electrical resistivity of fully strained substoichiometric epitaxial TiNx (0.67⩽x<1.0) layers on MgO(001)

Cited by 124 publications

References 34 publications

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

Nonequilibrium ab initio molecular dynamics determination of Ti monovacancy migration rates in B1 TiN

Ab initio and classical molecular dynamics simulations of N2 desorption from TiN(001) surfaces

Toughness enhancement in hard ceramic thin films by alloy design

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