6.10 STS of Si and Pd Nanostructures
135
the STM/S experiments at 4 K. Therefore, the Si-E G expansion and the energy shift
of both the 2p and the valance band are intrinsically correlated, which further verify
the essentiality and universality of the BOLS notion.
6.11 Summary
Consistency in the BOLS-NEP predictions, DFT calculations, STM/S, TEM, XPS,
and APECS measurements of CN dependence of the lattice strain, muffin-tin inner
potential depression, core level shift, and the chain end and island charge polarization of a number of metallic nanostructures confirmed the BOLS-NEP predictions. Atomic undercoordination is so important that it results in the local strain,
quantum entrapment, charge densification and the subjective valence charge polarization, which is responsible for the size dependence of known bulk properties and
size derivacy of anomalies that the bulk does never show. These emerging properties include the catalytic enhancement, toxicity, dilute magnetism, and Dirac-Fermi
polaritons in topological insulators, as well as conductor-insulator transition, etc.
Entrapment enlarges the electroaffinity and the band gap. Polarization lowers the
work function. These elemental quantities mediate intrinsically the performance of
a substance.
The localized polarization of the nonbonding s-electrons for Au(6s
1 ), Ag(5s
1 ),
Rh(5s
1 ) and Cu(4s
1 ) adatoms makes the conducting metal to be insulator at the
nanoscale. However, Pt(6s
0 ) adatoms, reconstructed Pt surface, Co(4s
2 ) islands, Co,
Si, and Ni nanocrystals show entrapment dominance, instead, because of the lacking of the unpaired s
1 charge, according to the BOLS expectation and the present
observations. In contrast, the strong valence polarization suggests the electronic configuration preference of the undercooordinated W(5d
1 6s
1 ) and Mo (4d
5 5s
1 ) atoms.
The consistence in the Si nanowire bandgap expansion, Pd bandgap generation, and
Si cluster 2p level and valence band shift evidence the essentiality and universality of
the BOLS notion and the associated quantum entrapment and subjective polarization.
References
1. C. Bittencourt, A. Felten, B. Douhard, J. Ghijsen, R.L. Johnson, W. Drube, J.J. Pireaux,
Photoemission studies of gold clusters thermally evaporated on multiwall carbon nanotubes.
Chem. Phys. 328(1–3), 385–391 (2006)
2. S.P. Suprun, E.V. Fedosenko, Low-temperature recrystallization of Ge nanolayers on ZnSe.
Semiconductors 41(5), 590–595 (2007)
3. J.G. Tao, J.S. Pan, C.H.A. Huan, Z. Zhang, J.W. Chai, S.J. Wang, Origin of XPS binding
energy shifts in Ni clusters and atoms on rutile TiO 2 surfaces. Surf. Sci. 602(16), 2769–2773
(2008)
4. I. Aruna, B.R. Mehta, L.K. Malhotra, S.M. Shivaprasad, Size dependence of core and valence
binding energies in Pd nanoparticles: interplay of quantum confinement and coordination
reduction. J. Appl. Phys. 104(6), 064308 (2008)
135
the STM/S experiments at 4 K. Therefore, the Si-E G expansion and the energy shift
of both the 2p and the valance band are intrinsically correlated, which further verify
the essentiality and universality of the BOLS notion.
6.11 Summary
Consistency in the BOLS-NEP predictions, DFT calculations, STM/S, TEM, XPS,
and APECS measurements of CN dependence of the lattice strain, muffin-tin inner
potential depression, core level shift, and the chain end and island charge polarization of a number of metallic nanostructures confirmed the BOLS-NEP predictions. Atomic undercoordination is so important that it results in the local strain,
quantum entrapment, charge densification and the subjective valence charge polarization, which is responsible for the size dependence of known bulk properties and
size derivacy of anomalies that the bulk does never show. These emerging properties include the catalytic enhancement, toxicity, dilute magnetism, and Dirac-Fermi
polaritons in topological insulators, as well as conductor-insulator transition, etc.
Entrapment enlarges the electroaffinity and the band gap. Polarization lowers the
work function. These elemental quantities mediate intrinsically the performance of
a substance.
The localized polarization of the nonbonding s-electrons for Au(6s
1 ), Ag(5s
1 ),
Rh(5s
1 ) and Cu(4s
1 ) adatoms makes the conducting metal to be insulator at the
nanoscale. However, Pt(6s
0 ) adatoms, reconstructed Pt surface, Co(4s
2 ) islands, Co,
Si, and Ni nanocrystals show entrapment dominance, instead, because of the lacking of the unpaired s
1 charge, according to the BOLS expectation and the present
observations. In contrast, the strong valence polarization suggests the electronic configuration preference of the undercooordinated W(5d
1 6s
1 ) and Mo (4d
5 5s
1 ) atoms.
The consistence in the Si nanowire bandgap expansion, Pd bandgap generation, and
Si cluster 2p level and valence band shift evidence the essentiality and universality of
the BOLS notion and the associated quantum entrapment and subjective polarization.
References
1. C. Bittencourt, A. Felten, B. Douhard, J. Ghijsen, R.L. Johnson, W. Drube, J.J. Pireaux,
Photoemission studies of gold clusters thermally evaporated on multiwall carbon nanotubes.
Chem. Phys. 328(1–3), 385–391 (2006)
2. S.P. Suprun, E.V. Fedosenko, Low-temperature recrystallization of Ge nanolayers on ZnSe.
Semiconductors 41(5), 590–595 (2007)
3. J.G. Tao, J.S. Pan, C.H.A. Huan, Z. Zhang, J.W. Chai, S.J. Wang, Origin of XPS binding
energy shifts in Ni clusters and atoms on rutile TiO 2 surfaces. Surf. Sci. 602(16), 2769–2773
(2008)
4. I. Aruna, B.R. Mehta, L.K. Malhotra, S.M. Shivaprasad, Size dependence of core and valence
binding energies in Pd nanoparticles: interplay of quantum confinement and coordination
reduction. J. Appl. Phys. 104(6), 064308 (2008)