arXiv subjects

Vincent Meunier

Publications and source records attributed to Vincent Meunier.

40 records · Page 3Linked to original sources

arXiv2009

First-principles methodology for quantum transport in multiterminal junctions

We present a generalized approach for computing electron conductance and I-V characteristics in multiterminal junctions from first-principles. Within the framework of Keldysh theory, electron transmission is evaluated employing an O(N) method for electronic-structure calculations. The nonequilibrium Green function for the nonequilibrium electron density of the multiterminal junction is computed self-consistently by solving Poisson equation after applying a realistic bias. We illustrate the suitability of the method on two examples of four-terminal systems, a radialene molecule connected to carbon chains and two crossed carbon chains brought together closer and closer. We describe charge density, potential profile, and transmission of electrons between any two terminals. Finally, we discuss the applicability of this technique to study complex electronic devices.

cond-mat.mtrl-sci↗

arXiv2009

Electron transport in multi-terminal molecular device

The electron transport properties of a four-terminal molecular device are computed within the framework of density functional theory and non-equilibrium Keldysh theory. The additional two terminals lead to new properties, including a pronounced negative differential resistance not present in a two-terminal setup, and a pseudo-gating effect. In general, quantum interference between the four terminals and the central molecule leads to a complex non-linear behavior, dependent on the alignment of individual molecular states under bias and their coupling to the leads.

cond-mat.mes-hall↗

arXiv2008

A new class of organic molecular magnets

Using detailed first principles calculations, we have found a new class of stable organic molecular magnets based on zwitterionic molecules possessing donor, $π$ bridge, and acceptor groups. These molecules are organic molecules containing only C, H and N. The quantum mechanical nature of the magnetic properties originates from the conjugated $π$ bridge (involving only p electrons) where the exchange interactions between electron spin are relatively strong and local and are independent of the length of the $π$ bridge, enabling the easy construction of a molecular magnetic device with specified length.

cond-mat.mtrl-sci↗

arXiv2007

Massless Fermions in multilayer graphitic systems with misoriented layers

We examine how the misorientation of a few stacked graphene layers affects the electronic structure of carbon nanosystems. We present {\it ab initio} calculations on bi- and trilayer systems to demonstrate that the massless Fermion behavior typical of single layered graphene is also found in incommensurate multilayered graphitic systems. We also investigate the consequences of this property on experimental fingerprints, such as Raman spectroscopy and scanning tunneling microscopy (STM). Our simulations reveal that STM images of turbostratic few layer graphite are sensitive to the layer arrangement. We also predict that resonant raman signal of graphitic samples are more sensitive to the orientation of the layers than to their number.

cond-mat.mtrl-sci↗