Spontaneous spin polarization in rubrene studied by density functional theory calculations

We theoretically studied the spontaneous spin polarization properties of organic molecule rubrene by using density functional theory calculations. Our investigations show that normally nonmagnetic molecule rubrene could be spin polarized by spinless-hole injection. Magnetic moment of the molecule increases linearly with the extra hole charge amount only when the injected hole charges reach a certain value. The spin density resides predominantly on the carbon atoms in the tetracene backbone of rubrene molecule and also the bond lengths change differently due to the injected charge. Spontaneous spin polarization can be explained as the preferably filling of the spin-splitted carbon pz orbitals near the Fermi energy for the injected charge.

Graphical abstractNormally nonmagnetic molecule rubrene could be spontaneous spin polarized by spinless-hole injection because of the preferably filling of the spin-splitted pz orbitals of carbon atoms in the tetracene backbone near the Fermi energy.Figure optionsDownload full-size imageDownload as PowerPoint slide