Magnetoresistance of granular Pt–C nanostructures close to the metal–insulator transition

Porrati, F.; Sachser, Roland; Huth, Michael

doi:10.1088/0953-8984/26/8/085302

Cited by 8 publications

(8 citation statements)

References 49 publications

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“…7 for a schematic phase diagram of nano-granular metals). Furthermore, there is growing evidence for the emergence of collective states, indicated by super-ferro-or super-antiferromagnetic behavior in nano-granular Pt in a certain range of the coupling strength g for temperatures below about 20 to 30 K [87,88].…”

Section: Ordered and Disordered Nano-granular Metalsmentioning

confidence: 99%

Focused electron beam induced deposition meets materials science

Huth

Porrati

Dobrovolskiy

2018

Microelectronic Engineering

157

172

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simulation-assisted growth of complex three-dimensional nano-architectures is also covered. In the review particular emphasis is laid on conceptual clarity in the description of the different developments, which is reflected in the mostly schematic nature of the presented figures, as well as in the recurring final sub-sections for each of the main topics discussing the respective "challenges and perspectives".

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Section: Ordered and Disordered Nano-granular Metalsmentioning

confidence: 99%

Focused electron beam induced deposition meets materials science

Huth

Porrati

Dobrovolskiy

2018

Microelectronic Engineering

157

172

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“…6 Moreover, the catalytic ability of Au, Pt, Pd, and Rh NPs is greatly enhanced; 7 and a phase transition from the conductor to the insulator happens at the nanometer scale. 8,9…”

Section: Introductionmentioning

confidence: 99%

Atomic under-coordination fascinated catalytic and magnetic behavior of Pt and Rh nanoclusters

Ahmadi

Zhang

Gong

et al. 2014

Phys. Chem. Chem. Phys.

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Density functional theory (DFT) calculations with local spin density discrimination have been performed to examine the effect of atomic under-coordination on the catalytic and magnetic properties of cuboctahedral (CO) and marks decahedral (MD) structured Pt and Rh nanoclusters. Consistency between theoretical calculations and experimental observations confirmed the predictions based on the framework of bond-order-length-strength (BOLS) correlation and nonbonding electron polarization (NEP) notations. The BOLS-NEP notation suggests that the shorter-and-stronger bonds between under-coordinated atoms induce local densification and quantum entrapment of core electrons, which then polarize the otherwise conducting electrons and result in shifts of the binding energy. Such strong localization resolves the intriguing catalytic and magnetic attributes of Pt and Rh nanoclusters.

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“…6 Nanomaterials demonstrate catalysis abilities and allow the transit of metallic nanoparticles from a conductor to an insulator for Ag and Pt, or a nonmagnetic-tomagnetic behavior for Pt and Rh nanoparticles, caused by pinning the conduction electrons. [7][8][9][10][11] The red shift of valence band is detected with scanning tunneling microscopy/spectroscopy (STM/S), which includes Ag clusters and chains on the Ag(111) substrate, 12 13 Cu adatom on the Cu(111) surface, 14 Cu chains on the Cu (111) substrate, 15 gold atomic chains, 16 Rh nanoparticles, 17 and Pt nanoclusters. 18 The positive core level energy instantaneously shifts to higher binding energy level in nanomaterials Chapter 1: Introduction when measured using X-ray photoelectron spectroscopy (XPS) for Ag, Cu, Pt, and Rh nanoparticles, 6,[19][20][21][22][23] resulting in perturbed Hamiltonian.…”

Section: List Of Tablesmentioning

confidence: 99%

“…133 Furthermore, the catalytic ability of Au, Pt, Pd, and Rh nanoparticles is greatly enhanced; 134 and a phase transition from conductor to insulator occurs at the nanometre scale. 10,11 Chapter 5: Quantum Entrapment and Valence Polarization of Pt and Rh Nanoclusters…”

Section: Cls and Lattice Strainmentioning

confidence: 99%

“…According to Eq. (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21), the B and Eν(∞) values are achieved by linearizing the measured data of Ag and Cu binding energy with respect to 1/K. Taking the obtained CLS value to the simulation iteration of the measured size-dependent Eν(K) for Ag deposited on CeO2 and HOPG substrates, m = 1.0000, similar to that of pure metals,4 …”

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confidence: 99%

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Quantum entrapment and valence charge polarization in Ag, Cu, Pt, and Rh nanoclusters

Ahmadi¹

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Atomic under-coordination and non-bonding electrons are extensively used in nanomaterials and nanostructures. The bonds between the under-coordinated sites follow the rule of relaxation dynamics, although quantum confinement (QC) theory, Coulomb blockade, and size-dependent dynamic effects cannot describe the change in Hamiltonian and other magnitudes. The effect of under-coordinated atom on the electronic structures of nanomaterials was calculated in this study using the bond-orderlength-strength (BOLS) correlation and non-bonding electron polarization (NEP) notations. The Hamiltonian perturbation of the atomic under-coordination entrapped the core electrons and polarized the valence charge. Consistency between the BOLS-NEP notation and density functional theory (DFT) calculations on Ag, Cu, Pt, and Rh nanoclusters with cuboctahedral (COh) and Marks decahedral (M-Dh) structures confirmed that the shorter and stronger bonds between atomic under-coordination induced local densification, quantum entrapment, and valence charge polarization. The strong localization determined the intriguing catalytic, magnetic, and plasmonic attributes of these metallic nanoclusters. The effect of excess charge states from (+2) to (-2) was determined using DFT calculations and BOLS correlation theories on the metallic nanoclusters with COh and M-Dh structures. Consistency between DFT calculations and experimental observations confirmed our BOLS predictions including the local bond length relaxation, charge investigated using excess charge states, including negative, neutral, and positive charges Chapter 1: Introduction 3 on the surface in both theoretical and experimental observations. 25-27 The excess charge states on the nanocluster surface play a significant role in the ability of catalysts in adjusting oxide support. Bond-order-length-strength (BOLS) correlation 28 has been used to refine the nonbonding electron polarization (NEP) theory, 3, 29, 30 to solve associated problems, 31, 32 including superfluidity in carbon nanotube channels, 33 superlubricity in dry sliding, 31, 34 and supersolidity of 4 He with superelasticity and superfluidity. 35 The effect of undercoordinated atoms and excess charge states on Ag, Cu, Pt, and Rh metallic nanoclusters are investigated in this study according to the BOLS-NEP theory. According to unique properties of these metallic nanoclusters such as magnetic and nonmagnetic order, and plasmon and catalyst applications, we are chosen Ag, Cu, Pt, and Rh metallic nanoclusters in this thesis. In addition, the results of Ag, Cu, Pt, and Rh metallic nanoclusters are presented separately, in Chapters 4 and 5, respectively, because Ag, Cu, Pt, and Rh belong to different elements such as Nobel and open metals. 1.2 Challenges The concept of broken bonds and non-bonding in nanomaterials is complicated. According to theoretical and experimental observations, valence band polarization, CLS, lattice strain, charge transfer, magnetization, optical application, and electronic properties of metallic nanoclusters ar...

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Magnetoresistance of granular Pt–C nanostructures close to the metal–insulator transition

Cited by 8 publications

References 49 publications

Focused electron beam induced deposition meets materials science

Focused electron beam induced deposition meets materials science

Atomic under-coordination fascinated catalytic and magnetic behavior of Pt and Rh nanoclusters

Quantum entrapment and valence charge polarization in Ag, Cu, Pt, and Rh nanoclusters

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