Today - CMSP Seminar (Atomistic Simulation Webinar Series): Wedn. 13 October 2021 at 11 a.m.

[CMSP Seminars Secretariat]

Today - Reminder

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Virtual - Zoom Meeting

CMSP Atomistic Simulation Webinar Series
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* * * *Wednesday, 13 October 2021 at 11:00 a.m.** * *

Speaker: *Matej Badin *(SISSA)

Title: *Nucleating a Different Coordination in a Crystal under Pressure: 
A Study of the B1-B2 Transition in NaCl by Metadynamics *

Register in advance at:
https://zoom.us/meeting/register/tJwvcOCvpjsqHdQM7OeIudf5SSxtk1ZZEaQQ
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Abstract:

Prediction of crystal structures has reached a high level of 
reliability, but much less is known about the mechanisms of structural 
transitions and pertinent barriers. The barriers related to nucleation 
of crystal structure inside another one are critically important for 
kinetics and eventually decide what structure will be created in experiment.

We demonstrate an NPT metadynamics simulation scheme ^[1] employing 
coordination number and volume as collective variables and illustrate 
its application on a well-known example of reconstructive structural 
transformation B1/B2 in NaCl. Studying systems with size up to 64000 
atoms we reach beyond the collective mechanism and observe the 
nucleation regime. We reveal the structure of the critical nucleus and 
calculate the free-energy barrier of nucleation and also uncover details 
of the atomistic transition mechanism and show that it is size-dependent.

Our approach is likely to be applicable to a broader class of structural 
phase transitions induced by compression/decompression and could find 
phases unreachable by standard crystal structure prediction methods as 
well as reveal complex nucleation and growth effects of martensitic 
transitions.

_^[1] Matej Badin and Roman Martoňák, Phys. Rev. Lett. 127, 105701 
<https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.127.105701> 
(2021)

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