@inproceedings{1ccdaafa16c84da0a564146b8383e714,

title = "Singlet-triplet ground-state instability in square quantum dot",

abstract = "We theoretically study the spin multiplicity in the ground state of the square quantum dot (SQD) including four electrons, and discuss a possibility of the singlet-triplet (S/T) instability in the quantum system. As predicted by Hund's rule, the ground-state triplet appears when the DQD has a point group symmetry of D 4h. This ground-state triplet is also found even in the deformed SQD (D 2h) if the confinement length L is elongated. Consequently, the S/T instability is expected along these boundary lines. It is also worthwhile to notice that the present DFT as well as UHF calculation predicts the spin-singlet ground-state when the inter-electron interaction is strengthened (larger L) even though the SQD maintains its geometrical form of D 4h. The strong electron-localization causes the destabilization in the orbital (kinetic) energies, and produces this characteristic {"}anti-Hund{"} state.",

keywords = "DFT, Hund's rule, UHF, quantum dot, singlet-triplet instability",

author = "Yuki Negishi and Masamu Ishizuki and Atsushi Tsubaki and Kyozaburo Takeda and Yusuke Asari and Takahisa Ohno",

year = "2011",

doi = "10.1063/1.3666471",

language = "English",

isbn = "9780735410022",

series = "AIP Conference Proceedings",

pages = "497--498",

booktitle = "Physics of Semiconductors - 30th International Conference on the Physics of Semiconductors, ICPS-30",

note = "30th International Conference on the Physics of Semiconductors, ICPS-30 ; Conference date: 25-07-2010 Through 30-07-2010",

}