Friction anomalies at first-order transition spinodals: 1T-TaS2. (15th February 2018)

• Record Type: Journal Article
• Authors: Panizon, Emanuele; Marx, Torben; Dietzel, Dirk; Pellegrini, Franco; Santoro, Giuseppe E; Schirmeisen, Andre; Tosatti, Erio
• Is Part Of: New journal of physics. Volume 20:Number 2(2018:Feb.)
• Publication Date: 2018-02-15
• Subjects: spinodal -- nanofriction -- 1T-TaS2 -- friction force microscopy; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/aaac00
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: Revealing phase transitions of solids through mechanical anomalies in the friction of nanotips sliding on their surfaces, a successful approach for continuous transitions, is still an unexplored tool for first-order ones. Owing to slow nucleation, first-order structural transformations occur with hysteresis, comprised between two spinodal temperatures where, on both sides of the thermodynamic transition, one or the other metastable free energy branches terminates. The spinodal transformation, a collective one-shot event without heat capacity anomaly, is easy to trigger by a weak external perturbation. Here we show that even the gossamer mechanical action of an AFM-tip can locally act as a trigger, narrowly preempting the spontaneous spinodal transformation, and making it observable as a nanofrictional anomaly. Confirming this expectation, the CCDW–NCCDW first-order transition of the important layer compound 1T-TaS2 is shown to provide a demonstration of this effect.