Statistical model of defects in Al-H system

Abstract

Vacancy and hydrogen concentrations in Al were determined by first-principles calculations and statisticalmechanics modeling, as functions of temperature and hydrogen chemical potential μH.

Stress in aluminum induced by hydrogen absorption during cathodic polarization

“…Several experimental studies have found consistent values of these quantities, as indicated inTable 2[24][25][26][27]. First-principles calculations have also yielded comparable formation energies of 0.6 -0.7 eV for absorption into interstitial lattice sites[28][29][30]. The force-potential curves predicted from Equation 10 using these values, and with η ad set to zero, are shown as the dashed black lines inFigure 4.…”

Gigantic Surface Lifetime of an Intrinsic Topological Insulator

“…Here, we report a remarkably long life-time exceeding 4 microseconds (1 µs = 10 −6 s) for the optically excited Dirac surface states. This is achieved by using a truly bulk insulating TI sample Bi 2 Te 2 Se (BTS221) with bulk resistivity larger than 6 Ωcm [23][24][25][26][27][28], where only the surface states cross the Fermi level. Surprisingly, we show that the observed long optical life-time in our BTS221 samples leads to a surface photo-voltage (a shift of the chemical potential of the Dirac surface states) as large as ∼ 100 mV, which is also observed to be robust on the time scale of microseconds.…”

“…Single crystalline samples of topological insulators used in our measurements were grown using the Bridgman method and characterized by spectroscopic and transport methods, which is detailed elsewhere [23][24][25][26][27]. The TrARPES setup at the Institute for Solid State Physics (ISSP) in University of Tokyo consists of an amplified Ti:sapphire laser system delivering hν= 1.47 eV pulses of 170-fs duration with 250-kHz repetition and a hemispherical analyzer [28,31].…”

Tensile stress and plastic deformation in aluminum induced by aqueous corrosion

“…(1) is about À1.5 eV. This m Al deficiency is more than twice the formation energy of bulk vacancies in Al [13], and therefore by itself would produce large equilibrium vacancy concentrations. In the dissolution experiments, vacancy formation is additionally promoted by the elevated hydrogen concentration.…”

“…Density functional theory (DFT) calculations indicate that hydrogen occupancy of as many as 12 octahedral interstitial sites neighboring the vacancy is energetically favorable [8,12,13,40]. Thermodynamic models based on DFT-derived energetics indicate that large concentrations of vacancy-hydrogen defects should be present at equilibrium with the hydrogen concentrations on the order of 0.1 at.…”