Electronic Stopping of Slow Protons in Transition and Rare Earth Metals: Breakdown of the Free Electron Gas Concept

Roth, D.; Bruckner, Barbara; Moro, Marcos V.; Gruber, S.; Goebl, D.; Juaristi, J. I.; Alducin, M.; Steinberger, R.; Duchoslav, Jiri; Primetzhofer, Daniel; Bauer, Péter

doi:10.1103/physrevlett.118.103401

Cited by 59 publications

(41 citation statements)

References 49 publications

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“…4) for both H and He projectiles; while low DOS above the Fermi level for NiFe, NiCo and Ni is responsible for the low S e compared to that of the NiCr target. Similar behavior was observed for transition and rare earth metals by Roth et al [55].…”

Section: Resultssupporting

confidence: 86%

“…From this insight, we can qualitatively explain the behavior of S e for the target species. NiCr has higher electronic DOS below and above E F , therefore allows for low energy excitations of electrons close to the Fermi surface with higher probabilities [55,56]. This is responsible for the relatively high S e observed for NiCr at low velocities (see Fig.…”

Section: Resultsmentioning

confidence: 95%

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Effect of Chemical Disorder on the Electronic Stopping of Solid Solution Alloys

et al. 2020

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The electronic stopping power of nickel-based equiatomic solid solutions alloys NiCr, NiFe and NiCo for protons and alpha projectiles is investigated in detail using real-time time-dependent density functional theory over a wide range of velocities. Recently developed numerical electronic structure methods are used to probe fundamental aspects of electron-ion coupling non-perturbatively and in a fully atomistic context, capturing the effect of the atomic scale disorder. The effects of particular electronic band structures and density of states reflect in the low velocity limit behavior. We compare our results for the alloys with those of a pure nickel target to understand how alloying affects the electronic stopping. We discover that NiCo and NiFe have similar stopping behavior as Ni while NiCr has an asymptotic stopping power that is more than a factor of two larger than its counterparts for velocities below 0.1 a.u.. We show that the low-velocity limit of electronic stopping power can be manipulated by controlling the broadening of the d-band through the chemical disorder. In this regime, the Bragg's additive rule for the stopping of composite materials also fails for NiCr. arXiv:1912.03399v1 [cond-mat.mtrl-sci]

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 95%

Effect of Chemical Disorder on the Electronic Stopping of Solid Solution Alloys

et al. 2020

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“…In evaluating the DOS, the occupancies of the electronic states are determined with the tetrahedron method. be interpreted in a similar way as electronic stopping of protons in metals [36]. Another aspect of these results is that for stopping of slow protons in an oxide AxO1-x, Bragg's rule is simplified since the contribution of the cations, A, can be set to zero.…”

Section: Fig 1 Ox Of Vo2 For H Ions (Protons and Deuterons) In Bothmentioning

confidence: 99%

“…for the same primary charge (similarly as in [36]). The reference targets (polycrystalline Cu and Au) were cleaned employing 3 keV Ar + sputtering; surface purity was checked by Auger electron spectroscopy (AES).…”

Section: (1 Kev Protons)mentioning

confidence: 99%

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Electronic Stopping of Slow Protons in Oxides: Scaling Properties

et al. 2017

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Electronic stopping of slow protons in ZnO, VO2 (metal and semiconductor phases), HfO2 and Ta2O5 was investigated experimentally. As a comparison of the resulting stopping cross sections (SCS) to data for Al2O3 and SiO2 reveals, electronic stopping of slow protons does not correlate with electronic properties of the specific material such as band gap energies.Instead, the oxygen 2p states are decisive, as corroborated by DFT calculations of the electronic densities of states. Hence, at low ion velocities the SCS of an oxide primarily scales with its oxygen density.

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A Physical Description of the Variability in Single‐ReRAM Devices and Hardware‐Based Neuronal Networks

Funck,

Wiefels,

Bengel

et al. 2023

Advanced Intelligent Systems

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Resistive switching devices are candidates to be used as weight for the future hardware realization of neuronal networks. Herein, these resistive switches base on oxygen vacancy migration and can be toggled between different resistance states. Internal processes lead to a variability over time in these states. To understand this, a dynamical model is developed, which links the internal physical mechanism to the current response. Thereby, the electronic current is calculated by tunneling processes over oxygen vacancies. The model allows to understand the physical transport properties and the current–voltage dependence. Integrating ionic hopping processes clarifies the variability in the electronic conduction. The derived model does not require empirical input parameters and only depends on the properties of the materials. This allows to use literature values and independently compare them to electrical measurements. The model predicts the experiments correctly. Thereupon, the physical properties of the conduction are investigated with respect to the transport over discrete energy levels, which change under the hopping of oxygen vacancies. Afterwards, the current level and variability are simulated for increasing oxygen vacancy concentrations to investigate analog switching, which is required for neuronal network layers. Finally, the variability is tested with multiple interacting cells in a neuronal layer.

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Electronic Stopping of Slow Protons in Transition and Rare Earth Metals: Breakdown of the Free Electron Gas Concept

Cited by 59 publications

References 49 publications

Effect of Chemical Disorder on the Electronic Stopping of Solid Solution Alloys

Effect of Chemical Disorder on the Electronic Stopping of Solid Solution Alloys

Electronic Stopping of Slow Protons in Oxides: Scaling Properties

A Physical Description of the Variability in Single‐ReRAM Devices and Hardware‐Based Neuronal Networks

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