Capturing the Flag: The Struggle for National Identity in Nonviolent Revolutions

One goal of nonviolent resistance movements is to legitimize themselves in opposition to governments by undermining the latter’s leadership. We argue nonviolent groups that can ‘own’ the national identity are more likely to succeed, as they can assert the legitimacy of their vision for the state, and persuade other sectors of society to support their cause. Our argument is supported by the Arab Spring uprisings, where those resistance movements that were able to identify and claim ownership over a homogeneous national identity were more successful in pressing their claims. We view national identity as a component of symbolic power in both successful and unsuccessful nonviolent revolutions. We supplement our argument via a comparison of the Arab Spring uprisings featuring Egypt, Bahrain, and Libya, with nonviolent movements of the past: the ‘early’ cases (Northern Ireland, Iran, and the Philippines) and the color revolutions (Serbia, Georgia, and the Ukraine). We posit that the role of national identity, while not a determinant of success, can play an important role in the struggle for legitimacy, which may help determine the prospects of success for these movements

Optical Studies of Zero-Field Magnetization of CdMnTe Quantum Dots: Influence of Average Size and Composition of Quantum Dots

We show that through the resonant optical excitation of spin-polarized excitons into CdMnTe magnetic quantum dots, we can induce a macroscopic magnetization of the Mn impurities. We observe very broad (4 meV linewidth) emission lines of single dots, which are consistent with the formation of strongly confined exciton magnetic polarons. Therefore we attribute the optically induced magnetization of the magnetic dots results to the formation of spin-polarized exciton magnetic polarons. We find that the photo-induced magnetization of magnetic polarons is weaker for larger dots which emit at lower energies within the QD distribution. We also show that the photo-induced magnetization is stronger for quantum dots with lower Mn concentration, which we ascribe to weaker Mn-Mn interaction between the nearest neighbors within the dots. Due to particular stability of the exciton magnetic polarons in QDs, where the localization of the electrons and holes is comparable to the magnetic exchange interaction, this optically induced spin alignment persists to temperatures as high as 160 K.Comment: 26 pages, 7 figs - submitted for publicatio

Tunneling magnetoresistance in noncollinear antiferromagnetic tunnel junctions

Antiferromagnetic (AFM) spintronics has emerged as a subfield of spintronics driven by the advantages of antiferromagnets producing no stray fields and exhibiting ultrafast magnetization dynamics. The efficient method to detect an AFM order parameter, known as the Néel vector, by electric means is critical to realize concepts of AFM spintronics. Here, we demonstrate that noncollinear AFM metals, such as Mn3Sn, exhibit a momentum dependent spin polarization which can be exploited in AFM tunnel junctions to detect the Néel vector. Using first-principles calculations, we predict a tunneling magnetoresistance (TMR) effect as high as 300% in AFM tunnel junctions with Mn3Sn electrodes, where the junction resistance depends on the relative orientation of their Néel vectors and exhibits four nonvolatile resistance states. We argue that the spin-split band structure and the related TMR effect can also be realized in other noncollinear AFM metals like Mn3Ge, Mn3Ga, Mn3Pt, and Mn3GaN. Our work provides a robust method for detecting the Néel vector in noncollinear antiferromagnets via the TMR effect, which may be useful for their application in AFM spintronic devices