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Compressibility of a Fermion Gas in Graphene
New Phys.: Sae Mulli 2018; 68: 1048~1051
Published online October 31, 2018;
© 2018 New Physics: Sae Mulli.

Gukhyung IHM*

Department of Physics, Chungnam National University, Daejeon 34134, Korea
Correspondence to:
Received September 10, 2018; Accepted September 27, 2018.
cc This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
We present the electronic compressibility of a Fermi gas in graphene. We focus on investigating both the temperature and the electron density dependences of the compressibility while neglecting electron-electron interactions and disorder effects. In previous studies, the temperature dependence of the compressibility has been neglected mainly due to its behavior being independent of temperature for ordinary two-dimensional electrons in a semiconductor. We use the Sommerfeld expansion method to obtain the relation between the chemical potential and the electron density, which is crutial in determining the compressibility. As a result, in contrast to ordinary two-dimensional electron systems, the compressibility of graphene has been shown to have a distinct temperature dependence of ~ $[E_F^2 - \frac{\pi^2}{3}(k_BT)^2]^{1/2}$.
PACS numbers: 73.22.Pr, 74.62.Fj
Keywords: Compressibility, Graphene, Sommerfeld expansion, Chemical potential

January 2019, 69 (1)
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