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The study of variation of the size, armchair and zigzag type effects on the melting process of graphene nanoribbons (GNR). A numerical thermodynamical model has been devoted for the study. The phase transition has first order behaviour. The formation of different defects, ring size and coordination number is dependent on the size and the edge type of GNR. The nuclei of heating appear at temperature around 2300 K and that can be considered as pre-melting point. | Communications in Physics, Vol. 26, No. 4 (2016), pp. 381-392 DOI:10.15625/0868-3166/26/4/8805 DEPENDENCE OF MELTING PROCESS ON SIZE AND EDGE TYPE OF GRAPHENE NANORIBBONS NGUYEN THI THUY HANG† Ho Chi Minh city University of Technology, Vietnam National University - Ho Chi Minh City, 268 Ly Thuong Kiet Street, ward 14, District 10, Ho Chi Minh City, Vietnam † E-mail: hangbk@hcmut.edu.vn Received 23 October 2016 Accepted for publication 17 February 2017 Abstract. The study of variation of the size, armchair and zigzag type effects on the melting process of graphene nanoribbons (GNR). A numerical thermodynamical model has been devoted for the study. The phase transition has first order behaviour. The formation of different defects, ring size and coordination number is dependent on the size and the edge type of GNR. The nuclei of heating appear at temperature around 2300 K and that can be considered as pre-melting point. The melting process shows the case that the results of Berezinsky-Kosterlitz-Thouless-NelsonHalperin-Young theory cannot be applied. Keywords: graphene nanoribbon, armchair, zigzag, size dependence, defects, phase transition. Classification numbers: 61.48.Gh, 61.46.-w, 81.05.ue. I. INTRODUCTION As is know that graphene has been intensively studied due to its peculiar physical properties [1, 2] and its potential applications for modern electronic devices [3–5]. However, graphene is zero-gap where the conduction and valence bands touch each other at a point called the Dirac point but do not overlap each other and this attribute makes a big problem for digital electronics [6]. Graphene nanoribbons (GNR) is one of the best solutions on this problem [7, 8]. It has been reported that GNR can be considered as a material with controllable band gap, depending on the edge structure and ribbon width [7–9]. It has also been suggested that zigzag type of GNR (ZGNR) may be considered as a perspective material for spintronics because it shows a half .
