Speaker
Dr
Antonio Cammarata
(Czech Technical University in Prague)
Description
One of the main difficulties in understanding and predicting frictional response is the intrinsic complexity of highly non-equilibrium processes in any tribological contact, which include breaking and formation of multiple interatomic bonds between surfaces in relative motion. Moreover, under tribological conditions, local charge accumulation may take place and affect the tribological behaviour of the corresponding neutral structure.
To understand the physical nature of the microscopic mechanism of friction and design new tribologic materials, we conducted a systematic quantum mechanic investigation at the atomic scale on prototipical Van der Waals MX2 (M=Mo, W; X=S, Se, Te) Transition Metal Dichalcogenides at different charge content. We combined the structural and dynamic information from group theoretical analysis and phonon band structure calculations with the characterisation of the electronic features using non-standard methods like orbital polarization and the recently formulated bond covalency, Normal-Mode Transition Approximation and cophonicity analyses. We formulated guidelines on how to engineer nanoscale friction, and finally applied them to design a new Ti-doped MoS2 phase.
Thanks to the strong correlation between the electronic and the dynamical features of these systems, the present outcomes can be promptly used to finely tune other physical properties for the design of new materials with diverse applications beyond tribology.
Ref.
A. Cammarata, T. Polcar, Nanoscale 9 (2017) 11488
A. Cammarata, T. Polcar, Phys. Rev. B 96 (2017) 085406
A. Cammarata, T. Polcar, Phys. Chem. Chem. Phys. 18 (2016) 4807.
A. Cammarata, T. Polcar, RSC Adv. 5 (2015) 106809.
A. Cammarata, T. Polcar, Inorg. Chem. 54 (2015) 5739.
A. Cammarata, J. Rondinelli, J. Chem. Phys. 141 (2014) 114704.
Primary author
Dr
Antonio Cammarata
(Czech Technical University in Prague)
