Chromium Porphyrin Arrays As Spintronic Devices

Abstract

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-PA(∞), 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 Å), 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-PA(∞). Electron transport of Cr-PA(1,2,3) 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-PA(2). 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.

Recent advances in computational studies of organometallic sheets: Magnetism, adsorption and catalysis

“…Such long-range magnetic coupling in the studied systems is related to the modulation via the TCNQ ligands. Besides, to explain the magnetic moment qualitatively, the authors proposed a model on d splitting named ''4 + 1 splitting'' [52]. This work provides theoretical insights leading to a better understanding of these novel frameworks and probes whether they are promising candidates for wide applications in MSA nanoelectronics.…”

Advantages of Prefabricated Tunnel Junction-Based Molecular Spintronics Devices

“…The TJMD approach, which is an extension of MTJ-based devices, 62 can be a practical solution to the MSD fabrication issues. MTJs can be easily transformed into a MSD; one only needs to use air-stable FM electrodes and suitable molecules 10,49,80 to realize such devices. One of the authors has contributed in the development of MTJ-based molecular devices.…”

First-principles study on the electronic, magnetic and spin transport properties of CU(6bpyNO)Cl2

“…The magnetism in organic-inorganic hybrid materials has attracted considerable research interest due to their potential in spintronic applications [1][2][3][4][5][6][7][8][9][10][11][12]. Recently, a new paramagnetic ligand, 2, 2'-bipyridin-6-yl tert-butyl nitroxide (6bpyNO) was synthesized, and then the compound Cu(6bpyNO)Cl 2 was obtained [13].…”