Magnetic phase diagram in a quasi-two-dimensional electron gas

✍ Scribed by Y. Ito; Y. Teraoka

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 188 KB
• Volume: 127
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/s0038-1098(03)00427-7

✦ Synopsis

Using spin density functional theory within the framework of the local spin density approximation with Perdew -Zunger type exchange-correlation energy, ferromagnetism in a quasi-two-dimensional electron gas (Q-2DEG) is studied. The electronic and magnetic structures of a thin film are calculated as a function of film thickness and electron density. Ferromagnetism in the Q-2DEG is found to appear at a higher electron density than in the three-dimensional electron gas. Unless a film is very thin, with decreasing electron density, a magnetic phase transition occurs from a spin-unpolarized fluid to a Wigner film with surface magnetism, in which the spin polarization localizes only in the neighborhood of surfaces. Further decreasing density induces another transition to a fully spin-polarized ferromagnetic Wigner film.