Chromium Porphyrin Arrays As Spintronic Devices

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• 作者：Woo Jong Cho ; Yeonchoo Cho ; Seung Kyu Min ; Woo Youn Kim ; Kwang S. Kim
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：June 22, 2011
• 年：2011
• 卷：133
• 期：24
• 页码：9364-9369
• 全文大小：936K
• 年卷期：v.133,no.24(June 22, 2011)
• ISSN：1520-5126

文摘

Spintronic devices are very important for futuristic information technology. Suitable materials for such devices should have half-metallic properties so that only one spin passes through the device. In particular, organic half metals have the advantage that they may be used for flexible devices and have a long spin-coherence length. We predict that the one-dimensional infinite chromium porphyrin array, which we call Cr鈥揚A_{鈭?/sub>, shows half-metallic behavior when the spins on the chromium atoms are in a parallel alignment. Since the chromium atoms are separated by a large distance (>8 脜), the coupling between spins is small and thus their directions can be readily controlled by an external magnetic field. In the ferromagnetic state, the band gap for major spin electrons is 0.30 eV, while there is no band gap for the minor spin electrons, thus reflecting the half-metallic property. This unique property originates from the high spin state of Cr which results in the spin asymmetry of the conduction band in Cr鈥揚A鈭?/sub>. Electron transport of Cr鈥揚A1,2,3 is calculated with the nonequilibrium Green function technique in the presence of Au electrodes. It turned out that the spin-filtering ability appears from the dimeric Cr鈥揚A2. Thus, a new organometallic framework for designing a spin filter is proposed. Though many others have designed novel spintronic devices, none of them are realized due to the lack of a practical fabrication method at present. However, the porphyrin-based spintronic device provides a synthesizable framework.}