{"abstracts":[{"sha1":"a4d7ebf65863ee95d043e9bb397b1ee2af9428c6","content":"Thermal properties of graphene monolayers are studied by path-integral\nmolecular dynamics (PIMD) simulations, which take into account the quantization\nof vibrational modes in the crystalline membrane, and allow one to consider\nanharmonic effects in these properties. This system was studied at temperatures\nin the range from 12 to 2000 K and zero external stress, by describing the\ninteratomic interactions through the LCBOPII effective potential. We analyze\nthe internal energy and specific heat and compare the results derived from the\nsimulations with those yielded by a harmonic approximation for the vibrational\nmodes. This approximation turns out to be rather precise up to temperatures of\nabout 400 K. At higher temperatures, we observe an influence of the elastic\nenergy, due to the thermal expansion of the graphene sheet. Zero-point and\nthermal effects on the in-plane and \"real\" surface of graphene are discussed.\nThe thermal expansion coefficient α of the real area is found to be\npositive at all temperatures, in contrast to the expansion coefficient\nα_p of the in-plane area, which is negative at low temperatures, and\nbecomes positive for T ≳ 1000 K.","mimetype":"text/plain","lang":"en"},{"sha1":"961f7b5566ae5096fcceacf95feb25083b2ca7fb","content":"Thermal properties of graphene monolayers are studied by path-integral\nmolecular dynamics (PIMD) simulations, which take into account the quantization\nof vibrational modes in the crystalline membrane, and allow one to consider\nanharmonic effects in these properties. This system was studied at temperatures\nin the range from 12 to 2000~K and zero external stress, by describing the\ninteratomic interactions through the LCBOPII effective potential. We analyze\nthe internal energy and specific heat and compare the results derived from the\nsimulations with those yielded by a harmonic approximation for the vibrational\nmodes. This approximation turns out to be rather precise up to temperatures of\nabout 400~K. At higher temperatures, we observe an influence of the elastic\nenergy, due to the thermal expansion of the graphene sheet. Zero-point and\nthermal effects on the in-plane and \"real\" surface of graphene are discussed.\nThe thermal expansion coefficient $\\alpha$ of the real area is found to be\npositive at all temperatures, in contrast to the expansion coefficient\n$\\alpha_p$ of the in-plane area, which is negative at low temperatures, and\nbecomes positive for $T \\gtrsim$ 1000~K.","mimetype":"application/x-latex","lang":"en"}],"refs":[],"contribs":[{"index":0,"raw_name":"Carlos P. Herrero","role":"author"},{"index":1,"raw_name":"Rafael Ramirez","role":"author"}],"license_slug":"ARXIV-1.0","language":"en","version":"v1","ext_ids":{"arxiv":"1709.05148v1"},"release_year":2017,"release_date":"2017-09-15","release_stage":"submitted","release_type":"article","webcaptures":[],"filesets":[],"files":[{"release_ids":["44vtittfpfaw5gv7pcjhmmwpl4"],"mimetype":"application/pdf","urls":[{"url":"https://arxiv.org/pdf/1709.05148v1.pdf","rel":"repository"},{"url":"https://web.archive.org/web/20191014230122/https://arxiv.org/pdf/1709.05148v1.pdf","rel":"webarchive"}],"sha256":"bdaee6f0cb58c5be52ad5f6853d5356f06ac19c78356f755a7b8ba951208856e","sha1":"fcba5036afbac5743249ab61816a02203071a831","md5":"ee7d69c4682cc746b12c879fc0305f66","size":309258,"revision":"552a19d8-7c70-4527-ab30-a97da9f71bd1","ident":"jpchqjkerrgozbgmtlb7szi54u","state":"active"}],"work_id":"aww2jb7rxbdlxc773cxwhar5jm","title":"Thermal properties of graphene from path-integral simulations","state":"active","ident":"44vtittfpfaw5gv7pcjhmmwpl4","revision":"105c5f45-8457-436b-b95c-8d0bf73d1858","extra":{"arxiv":{"base_id":"1709.05148","categories":["cond-mat.mtrl-sci","physics.chem-ph"],"comments":"13 pages, 10 figures","journal_ref":"J. Chem. Phys. 148, 102302 (2018)"}}}