Molecular dynamics simulations of hysteresis loops for BaTiO3 ferroelectric thin-film capacitors using the feram code

4 September 2009 (Fri) 15:30 – 17:00

5F seminar room, Sengen site

Dr. Takeshi Nishimatsu(西松毅博士)

Institute for Materials Research, Tohoku University (東北大学金属材料研究所)

Molecular dynamics simulations of hysteresis loops for BaTiO3 ferroelectric thin-film capacitors using the feram code

Molecular dynamics (MD) simulations of hysteresis loops are performed for bulk and thin-film BaTiO3 using our original MD code, "feram" (http://loto.sf.net/feram/) [1]. "feram" can simulate temperature, thickness, frequency and electrode dependences of ferroelectric properties. We confirmed that the imperfect screening by the electrodes decreases the coercive field as the film thickness decreases in thin-film ferroelectric capacitors, as described in Ref. [2]. We also found that compressive strain arising from epitaxial constraints suppresses the polarization switching, while the inclusion of inhomogeneous strain (i.e. acoustic displacements) eases the switching.

[1] Takeshi Nishimatsu, Umesh V. Waghmare, Yoshiyuki Kawazoe, and David Vanderbilt: Phys. Rev. B 78 (2008) 104104.

[2] M. Dawber, P. Chandra, P. B. Littlewood and J. F. Scott: J. Phys.-Condes. Matter 15 (2003) L393.

Dr. Taizo Sasaki(佐々木泰造)