2,635 research outputs found
Charge distribution and screening in layered graphene systems
Full text linkThe charge distribution induced by external fields in finite stacks of
graphene planes, or in semiinfinite graphite is considered. The interlayer
electronic hybridization is described by a nearest neighbor hopping term, and
the charge induced by the self consistent electrostatic potential is calculated
within linear response (RPA). The screening properties are determined by
contributions from inter- and intraband electronic transitions. In neutral
systems, only interband transitions contribute to the charge polarizability,
leading to insulating-like screening properties, and to oscillations in the
induced charge, with a period equal to the interlayer spacing. In doped
systems, we find a screening length equivalent to 2-3 graphene layers,
superimposed to significant charge oscillations.Comment: 8 page
Ultra-Short Optical Pulse Generation with Single-Layer Graphene
Full text linkPulses as short as 260 fs have been generated in a diode-pumped low-gain
Er:Yb:glass laser by exploiting the nonlinear optical response of single-layer
graphene. The application of this novel material to solid-state bulk lasers
opens up a way to compact and robust lasers with ultrahigh repetition rates.Comment: 6 pages, 3 figures, to appear in Journal of Nonlinear Optical Physics
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Epistemic Violence in the Process of Othering: Real-World Applications and Moving Forward
Get PDFFrom the work of Pierre Bourdieu on symbolic violence came the study of epistemic violence, which is at the core of the process of othering marginalized groups. Epistemological scholars including Kristie Dotson, Miranda Fricker, Cynthia Townley, and Gayatri Spivak have done extensive work on the theory of the phenomenon; it is necessary to analyze the classifications of epistemic violence through their application in empirical settings. Addressing three case studies of âotheringâ highlights the importance of greater integration of marginalized groups into the education system as the necessary first step towards eliminating othering by targeting epistemic violence at a base level
Outlawry and the Experience of the (Im)possible: Deconstructing Biopolitics
Get PDFOutlawry is a legal penalty that banishes wrongdoers from the community; it refers to a refusal to obey the law and a withdrawal of legal rights. Although outlawry is obsolete in western criminal law, Giorgio Agamben links it to modern biopolitics. As outlawry is appropriated to preserve the law, and as the law takes life as its object, the subject of politics disappears. Yet biopolitics also occurs alongside a threat to sovereignty posed by outlawry, and a shift away from the subject as a site of emancipatory politics, toward a politics of difference. Taking a post-structural approach, this project examines outlawry as a deconstructive concept. Outlawry exposes the lawâs inability to be at one with itself, its undecidability, and its dependence on fiction and force to come into being and to maintain itself. Staging outlawry in the terms of Carl Schmitt, Walter Benjamin, and Jacques Derrida, the first chapter develops outlawry as deconstructive concept with an undecidable relationship to justice. Chapter two looks to Judith Butlerâs performative subject and Louis Althusserâs theory of subject interpellation to re-think the relations between subject and law in light of outlawry. Chapter three examines the overlap between sovereignty, outlawry and the beast (la bĂȘte) discussed by Agamben and Derrida, and considers political concepts that might deter the conserving power of outlawry in favor of its deconstructive force. Finally, I turn to Levinasian ethics and Deleuze and Guattariâs concept of becoming-minoritarian to sketch a politics of outlawry that revises the law according to an ethical responsibility to the Other, the political agency of those who are excluded from the law, and their demand that structures of power be altered. Outlawry need not result in sheer abjection; for both the subject, and the anarchic demos, it can be a source of political vitality and social transformation. Yet as the atrocities of modernity bear witness, from the Shoah to Guantanamo Bay, outlawry can lead to âthe worst.â Outlawry marks the fault line between justice and injustice; if we are to achieve an ethical future, we must remain politically vigilant, self-critical and open to alterity
Electron-electron interaction and charging effects in graphene quantum dots
Full text linkWe analyze charging effects in graphene quantum dots. Using a simple model,
we show that, when the Fermi level is far from the neutrality point, charging
effects lead to a shift in the electrostatic potential and the dot shows
standard Coulomb blockade features. Near the neutrality point, surface states
are partially occupied and the Coulomb interaction leads to a strongly
correlated ground state which can be approximated by either a Wigner crystal or
a Laughlin like wave function. The existence of strong correlations modify the
transport properties which show non equilibrium effects, similar to those
predicted for tunneling into other strongly correlated systems.Comment: Extended version accepted for publication at Phys. Rev.
Adhesion, Stiffness and Instability in Atomically Thin MoS2 Bubbles
Full text linkWe measured the work of separation of single and few-layer MoS2 membranes
from a SiOx substrate using a mechanical blister test, and found a value of 220
+- 35 mJ/m^2. Our measurements were also used to determine the 2D Young's
modulus of a single MoS2 layer to be 160 +- 40 N/m. We then studied the
delamination mechanics of pressurized MoS2 bubles, demonstrating both stable
and unstable transitions between the bubbles' laminated and delaminated states
as the bubbles were inflated. When they were deflated, we observed edge pinning
and a snap-in transition which are not accounted for by the previously reported
models. We attribute this result to adhesion hysteresis and use our results to
estimate the work of adhesion of our membranes to be 42 +- 20 mJ/m^2
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