Thermodynamics beyond isolated Dirac points: A (possible) phase transition when coalescing

Departamento de Física, FACI, Universidad de Tarapacá - Casilla 7-D, Arica, Chile

^(a) E-mail: cflores@academicos.uta.cl (corresponding author)

Received: 26 December 2022
Accepted: 20 March 2023

Abstract

Graphene is certainly a prototype of Dirac's fermion in solid physics and has been extensively considered theoretically and experimentally. Nevertheless, here we go beyond the so-called Dirac's points considering the entire spectrum. More specifically, thermodynamic properties in a large range of energies are analyzed. Relationships between entropy, internal energy, specific heat, and temperature are considered. The topology of the spectrum changes drastically beyond Dirac's points and a phase transition appears. The technique used is through the treatment of images for counting the number of states for a given energy.