News

Electronegativity of atoms
May/17 paper in Nature Comm. »more info

Transfer of chirality
Feb/17 Paper published in Nature Chemistry including News&Views. »more info

Towards chemical recognition of molecules
Aug/16 Paper published in ACS Nano. »more info

Odehnal award
June/16 O. Stetsovych received Odehnal award »more info

Praemium Academiae
June/16 P. Jelinek received CAS award »more info

Imaging electrostatic field
May/16 paper in Nature Comm. »more info

O. Wichterle prize
May/16 P. Hapala received O. Wichterle prize for outstanding young scientists at the AS CR. »more info

On-surface chemical synthesis
Apr/16 paper in JACS »more info

Structural and Electronic Properties of Nitrogen-Doped Graphene
Mar/16 Paper in Phys. Rev. Lett. »more info

Role of the electrostatic force in AFM images
Mar/16 Paper in Phys. Rev. Lett »more info

Charge transport between two molecules
Sep/15 Paper in Phys. Rev. Lett »more info

The best poster ECOSS-31
Sep/15 Our work has been selected as the best poster in the ECOSS-31 conference. »more info

Paper in ACS Nano
Aug/15 Novel way of B,N-co doping of graphene demonstrated. »more info

paper in PRL and Physics
Aug/15 Our work has been published in Phys. Rev. Lett highlighted as Synopsis in Physics. »more info

Paper in Nature Comm.
Jul/15 High-resolution AFM images reported at room temperature. »more info

Paper in Nano Letters
Jun/15 The current and the force used for controlled atomic switching of silicon tetramer. »more info

O. Wichterle prize
May/15 M. Ondracek received O. Wichterle prize for outstanding young scientists at the AS CR. »more info

Fundamental relation between tunneling current and chemical force

There is a fundamental correlation between tunelling current and formed chemical bond.Both tunelling current and the chemical force between two bodies are driven by wave-function overlap between their outermost atoms.We demonstrated that the quantum degeneracy determines the fundamental relationship between the conductance G and the chemical force F acting between two bodies in atomic-sized contacts. Namely, depending on the contact conditions, the following proportionalities hold, either G ~ F or G~F2. We demonstrate that the presence of the later one, G~F2, is driven by the quantum degeneracy between frontiers electronic states [3]. To prove the presence of this quantum degeneracy phenomenon we deliberately have chosen the Si(111)-7x7 surface which possesses strongly localized dangling bond states. By means of a careful combination of precise simultaneous AFM/STM measurements with DFT simulations, we demonstrate that the G~F2 relation holds in point contacts formed between scanning probe and silicon adatoms on the Si(111)-7x7 surface [3]. We also developed a simple model, which provides a transparent explanation of the observed phenomena.

[1] M. Ternes, C. González, Ch. P. Lutz, P. Hapala, F.J. Giessibel, P. Jelínek, A.J. Heinrich
Interplay of Conductance, Force, and Structural Change in Metallic Point Contacts.
Phys. Rev. Lett. 106 (2011) 016802(1) - 016802(4).

[2] P. Jelínek, M. Ondráček, F. Flores
Relation between the chemical force and the tunnelling current in atomic point contacts: a simple model
J. Phys.-Condens. Mat. 24 (2012) 084001(1) - 084001(10).

1. Y. Sugimoto, M. Ondráček, , M. Abe, P. Pou ,S. Morita, , R. Pérez, F. Flores, P. Jelínek, Quantum Degeneracy in Atomic Point Contacts Revealed by Chemical Force and ConductancePhys. Rev. Lett. 111, 106803 (2013).