Quantum Mechanical Models of Metal Surfaces and Nanoparticles

Gräfe, Wolfgang

doi:10.1007/978-3-319-19764-7

Cited by 4 publications

(1 citation statement)

References 10 publications

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“…Heat engines have been investigated also in the quantum domain both at thermal equilibrium [30][31][32][33][34][35][36][37][38] and out of equilibrium [39][40][41][42][43][44][45][46][47][48][49]. Quantum effects become relevant already in systems at the nanoscale and in modern nanotechnologies that exhibit intermediate behaviours between classical and quantum regimes [14,50,51]. Considerable advances have been done to observe the in- * ugo.marzolino@ts.infn.it termediate regime by tuning system parameters [52][53][54][55][56].…”

Section: Introductionmentioning

confidence: 99%

Quantum thermochemical engines

Marzolino¹

2022

Preprint

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Convertion of chemical energy into mechanical work is the fundamental mechanism of several natural phenomena at the nanoscale, like molecular machines and Brownian motors. Quantum mechanical effects are relevant for optimising these processes and to implement them at the atomic scale. This paper focuses on engines that transform chemical work into mechanical work through energy and particle exchanges with thermal sources at different chemical potentials. Irreversibility is introduced by modelling the engine transformations with finite-time dynamics generated by a time-depending quantum master equation. Quantum degenerate gases provide maximum efficiency for reversible engines, whereas the classical limit implies small efficiency. For irreversible engines, both the output power and the efficiency at maximum power are much larger in the quantum regime than in the classical limit. The analysis of ideal homogeneous gases grasps the impact of quantum statistics on the above performances, which persists in the presence of interactions and more general trapping. The performance dependence on different types of Bose-Einstein Condensates (BECs) is also studied. BECs under considerations are standard BECs with a finite fraction of particles in the ground state, and generalised BECs where eigenstates with parallel momenta, or those with coplanar momenta are macroscopically occupied according to the confinement anisotropy. Quantum statistics is therefore a resource for enhanced performances of converting chemical into mechanical work.

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Section: Introductionmentioning

confidence: 99%

Quantum thermochemical engines

Marzolino¹

2022

Preprint

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In Situ Atomic‐Scale Observation of Kinetic Pathways of Sublimation in Silver Nanoparticles

Wang

et al. 2019

Advanced Science

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Uncovering kinetics of sublimation atomically is critical to understanding both natural phenomena and advanced manufacturing technologies. Here, direct in situ atomic‐scale observations to understand the effects of size, surface, and defects in the sublimation process of supported silver nanoparticles upon heating within an aberration‐corrected transmission electron microscopy are conducted. Atomic‐scale evidence to sublimation and atomic rearrangement in small Ag nanoparticles during heating is provided, and it is demonstrated that the sublimation‐induced stable surfaces in the particles with a size smaller than ≈30 nm are {111} and {100} planes. The role of surface energy and defects in the uniform and nonuniform sublimation pathways at the atomic scale is also revealed, and it is found that the nanoparticles with low surface energy tend to undergo a uniform sublimation pathway, while those with high surface energy or five‐fold twin grain boundary proceed via a nonuniform sublimation pathway. Further dynamic analysis unravels a critical size of ≈8 nm for the transformation from linear to nonlinear sublimation rates in the two pathways. These findings demonstrate that the size, shape, and defects are of paramount importance for the sublimation dynamics in the first‐order phase transformation, helping to advance the general understanding of many technological applications.

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Topological states in the Kronig–Penney model with arbitrary scattering potentials

Reshodko

Benseny

Romhányi³

et al. 2019

New J. Phys.

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We use an exact solution to the fundamental finite Kronig-Penney model with arbitrary positions and strengths of scattering sites to show that this iconic model can possess topologically nontrivial properties. By using free parameters of the system as extra dimensions we demonstrate the appearance of topologically protected edge states as well as the emergence of a Hofstadter butterfly-like quasimomentum spectrum, even in the case of small numbers of scattering sites. We investigate the behavior of the system in the weak and strong scattering regimes and observe drastically different shapes of the quasimomentum spectrum.

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Quantum Mechanical Models of Metal Surfaces and Nanoparticles

Abstract: Quantum Mechanical Models of Metal Surfaces and Nanoparticles SpringerBriefs in Applied Sciences and TechnologyMore information about this series at

Cited by 4 publications

References 10 publications

Quantum thermochemical engines

Quantum thermochemical engines

In Situ Atomic‐Scale Observation of Kinetic Pathways of Sublimation in Silver Nanoparticles

Topological states in the Kronig–Penney model with arbitrary scattering potentials

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