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Campus de Excelencia InterncionalCampus of International Excellence

Agenda

Todos

Total 100 eventos
Agenda de eventos
FechaEvento
27/10/2017 - 27/10/2017Evolution of Coronaviruses

 

 

09/10/2017 - 09/10/2017Playing with molecular junctions – tales from the south

Abstract:  

The ultimate goal of molecular electronics is to create technologies that will complement—and eventually supersede—Si-based microelectronics technologies. To reach this goal, the field of single-molecule electronics is aiming at recognizing and characterizing single-molecule devices that mimic at least some of the behaviors of today's semiconductor components. In this talk I tell the tale of three such single-molecule devices, including the world’s smallest diode and the symmetric photo-switch, all of which are the fruit of collaboration with the experimental group of B.-Q. Xu. I describe both experimental (to the best of my powers) and theoretical sides of these devices, and elucidate the basic physical processes which are dominating these systems.

 

References:

1.        J. Zhou, S. Samanta, C. Guo, J. Locklinb and B. -Q. Xu, Measurements of contact specific low-bias negative differential resistance of single metalorganic molecular junctions, Nanoscale 5, 5715 (2013).

2.        Y. Dubi,  Dynamical coupling and negative differential resistance from interactions across the molecule-electrode interface in molecular junctions,  J. Chem. Phys. 139, 154710 (2013).

B.-Q. Xu and Y. Dubi, invited review: Negative Differential Conductance in Molecular Junctions: An Overview of Experiment and Theory, J. Phys. Condensed Matter 27, 263202 (2015).

C. Guo, K. Wang, E. Zerah-Harush, J. Hamill, B. Wang, Y. Dubi, B. Xu, Molecular rectifier composed of DNA with highrectification ratio enabled by intercalation, Nature Chemistry, doi:10.1038/nchem.2480 (AOP, 2016).

 

Más información: http://www.ifimac.uam.es/category/seminars/

09/10/2017 - 09/10/2017Computational study of the collective motion of micro-swimmers

 

Abstract:  

Micro-swimmers are active matter (AM), where AM can be seen as systems

composed of self-driven units, active particles, each capable of converting stored

or ambient free energy into systematic movement. Active materials are

intrinsically out of equilibrium and their collective behavior emerges from their

dynamic self-organization. Examples of active systems are found in all length

scales and could be classified in living and nonliving systems like individual living

cells, tissues and organisms, animal groups, self-propelled colloids and artificial

nanoswimmers. Particularly, in the micro and nano scale we find an enormous

range of interesting systems either biological or artificial, the spermatozoa that

fuse with the ovum during fertilization, the bacteria that inhabit our guts, the

protozoa in our ponds, the algae in the ocean; these are but a few examples of a

wide biological spectrum. Whereas in the artificial world we have self-healing

colloidal crystals and membranes to self-assembled microswimmers and robots.

Experiments in this field are now developing at a very rapid pace and new theoretical ideas are needed to bring unity to the field and identify “universal” behavior in these internally driven systems.

With numerical simulations we are able to find the fundamental role that the hydrodynamic coupling through the embedding solvent has in the collective behaviour in model systems of self-propelled microswimmers.

Such a fundamental understanding will help us to identify new routes to design micro-robots that can imitate micro-organisms and it might become possible to design materials that assemble and repair themselves from their microscopic components.

 

Más información: http://www.ifimac.uam.es/category/seminars/

22/09/2017 - 22/09/2017Polymer-theory insights into biomolecular systems

 

Abstract:  

Biomolecular systems are nowadays being the focus of a massive amount of research, both theoretical and experimental. The advancement of techniques has enabled the exploration of single-molecule properties, thus posing new challenges at the theoretical level. In this talk I will present two recent works inspired by such findings.

- The first part will be focused on a constitutive model for amyloid fibrils based on the minimization of the total energy per fibril. The constitutive model quantitatively recapitulates the main mesoscopic topological features of amyloid fibrils, that is, the evolution of fibril periodicity as a function of the ionic strength of the solution and of the fibril width.

A universal mesoscopic structural signature of the fibrils emerges from this picture, predicting a general, parameter-free law for the periodicity of the fibrils, that depends solely on the number of protofilaments per fibril. These predictions are validated experimentally and conclusively highlight the role of competing electrostatic and elastic contributions as the main players in the establishment of amyloid fibrils structure.

- The second work is focused on the shape and the orientational properties of a polymer chain under tension in a good solvent, a physical condition that is often realized both in single-molecule experiments and in vivo. Our findings reveal the existence of hitherto unobserved universal laws encompassing polymers with different rigidities and including the possible presence of excluded-volume effects, showing that both shape and orientation are solely determined by the force contribution to the free energy. In doing so, they also provide a simple way to retrieve these quantities from the knowledge of the force-versus-extension curve.

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

18/09/2017 - 18/09/2017Fabrication of Gold Nano-Crystal Arrays for Molecular Electronics: High Frequency Molecular Rectifiers and π-π Inter Molecular Interaction Energy

 

Abstract:  

E-beam lithography was used for versatile fabrication of sub-15 nm single-crystal gold nanoarrays at wafer-scale by the so-called dot on the fly (DOTF) technique [1]. Here DOTF and other methods are compared evidencing the limiting factors for the writing speed. Wafer-scale fabrication of such arrays with 50 nm pitch allowed XPS analysis of a ferrocenylalkyl thiol self- assembled monolayer coated gold nanoarray. We exploit these arrays as a suitable test bed for Molecular Electronics (ME) [2] and propose two studies on high frequency molecular rectifiers [3] and inter molecular Interactions [4].

 

In a first study, we demonstrate molecular diodes operating up to 17.8 GHz. Direct current and radio frequency (RF) properties were simultaneously measured with the tip of an interferometric scanning microwave microscope and S11 parameters show a diode rectification ratio of 12 dB. In a second investigation, we explore the π-π intermolecular interactions. This factor is one of the most important to optimize the transport and optical properties of organic transistors, light-emitting diodes or (bio-) molecular devices. Electrochemical measurements indicate two different phases localized on top and facets of the nanocrystals with clear intermolecular interactions and electrical current statistics on ~3000 molecular junctions confirm the theoretical prediction [5] of asymmetrical histograms due to cooperative effects.

 

References:

 

[1] J. Trasobares, F. Vaurette, M. François, H. Romijn, J-L. Codron, D. Vuillaume, D. Théron and N.

Clément. High speed e-beam lithography for gold nanoarray fabrication and use in nanotechnology. Beilstein J. Nanotechnol. 5, 1918–1925 (2014).

[2] N. Clement, G. Patriarche, K, Smaali, F. Vaurette, K. Nishiguchi, D. Troadec, A. Fujiwara, D. Vuillaume. Large array of sub-10-nm single-grain Au nanodots for use in nanotechnology. Small, 7, 2607 (2011).

[3] J. Trasobares, D. Vuillaume, D. Théron, N. Clement, A 17 GHz Molecular Rectifier, Nat.Commun. 7, 12850 (2016).

[4] J. Trasobares, J. Rech, T. Jonckeere, T. Martin, O. Aleveque, E. Levillain, V. Diez-Cabanes, Y. Olivier, J. Cornil, J.P. Nys, R. Sivakumarasamy, K. Smaali, Ph. Leclère, A. Fujiwara, D. Théron, D. Vuillaume, N. Clément. Estimation of π-π Electronic Couplings from Current Measurements. Nano Letters, 17, 3215-3224 (2017).

[5] M.G. Reuter, M.C. Hersam, T. Seideman, M.A. Ratner. Signatures of cooperative effects and transport mechanisms in conductance histograms. Nano Letters, 12, 2243-2248 (2012).

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

 

 

 

Destacados

No existen eventos destacados en esta categoría

Generales

Total 100 eventos
Agenda de eventos
FechaEvento
27/10/2017 - 27/10/2017Evolution of Coronaviruses

 

 

09/10/2017 - 09/10/2017Playing with molecular junctions – tales from the south

Abstract:  

The ultimate goal of molecular electronics is to create technologies that will complement—and eventually supersede—Si-based microelectronics technologies. To reach this goal, the field of single-molecule electronics is aiming at recognizing and characterizing single-molecule devices that mimic at least some of the behaviors of today's semiconductor components. In this talk I tell the tale of three such single-molecule devices, including the world’s smallest diode and the symmetric photo-switch, all of which are the fruit of collaboration with the experimental group of B.-Q. Xu. I describe both experimental (to the best of my powers) and theoretical sides of these devices, and elucidate the basic physical processes which are dominating these systems.

 

References:

1.        J. Zhou, S. Samanta, C. Guo, J. Locklinb and B. -Q. Xu, Measurements of contact specific low-bias negative differential resistance of single metalorganic molecular junctions, Nanoscale 5, 5715 (2013).

2.        Y. Dubi,  Dynamical coupling and negative differential resistance from interactions across the molecule-electrode interface in molecular junctions,  J. Chem. Phys. 139, 154710 (2013).

B.-Q. Xu and Y. Dubi, invited review: Negative Differential Conductance in Molecular Junctions: An Overview of Experiment and Theory, J. Phys. Condensed Matter 27, 263202 (2015).

C. Guo, K. Wang, E. Zerah-Harush, J. Hamill, B. Wang, Y. Dubi, B. Xu, Molecular rectifier composed of DNA with highrectification ratio enabled by intercalation, Nature Chemistry, doi:10.1038/nchem.2480 (AOP, 2016).

 

Más información: http://www.ifimac.uam.es/category/seminars/

09/10/2017 - 09/10/2017Computational study of the collective motion of micro-swimmers

 

Abstract:  

Micro-swimmers are active matter (AM), where AM can be seen as systems

composed of self-driven units, active particles, each capable of converting stored

or ambient free energy into systematic movement. Active materials are

intrinsically out of equilibrium and their collective behavior emerges from their

dynamic self-organization. Examples of active systems are found in all length

scales and could be classified in living and nonliving systems like individual living

cells, tissues and organisms, animal groups, self-propelled colloids and artificial

nanoswimmers. Particularly, in the micro and nano scale we find an enormous

range of interesting systems either biological or artificial, the spermatozoa that

fuse with the ovum during fertilization, the bacteria that inhabit our guts, the

protozoa in our ponds, the algae in the ocean; these are but a few examples of a

wide biological spectrum. Whereas in the artificial world we have self-healing

colloidal crystals and membranes to self-assembled microswimmers and robots.

Experiments in this field are now developing at a very rapid pace and new theoretical ideas are needed to bring unity to the field and identify “universal” behavior in these internally driven systems.

With numerical simulations we are able to find the fundamental role that the hydrodynamic coupling through the embedding solvent has in the collective behaviour in model systems of self-propelled microswimmers.

Such a fundamental understanding will help us to identify new routes to design micro-robots that can imitate micro-organisms and it might become possible to design materials that assemble and repair themselves from their microscopic components.

 

Más información: http://www.ifimac.uam.es/category/seminars/

22/09/2017 - 22/09/2017Polymer-theory insights into biomolecular systems

 

Abstract:  

Biomolecular systems are nowadays being the focus of a massive amount of research, both theoretical and experimental. The advancement of techniques has enabled the exploration of single-molecule properties, thus posing new challenges at the theoretical level. In this talk I will present two recent works inspired by such findings.

- The first part will be focused on a constitutive model for amyloid fibrils based on the minimization of the total energy per fibril. The constitutive model quantitatively recapitulates the main mesoscopic topological features of amyloid fibrils, that is, the evolution of fibril periodicity as a function of the ionic strength of the solution and of the fibril width.

A universal mesoscopic structural signature of the fibrils emerges from this picture, predicting a general, parameter-free law for the periodicity of the fibrils, that depends solely on the number of protofilaments per fibril. These predictions are validated experimentally and conclusively highlight the role of competing electrostatic and elastic contributions as the main players in the establishment of amyloid fibrils structure.

- The second work is focused on the shape and the orientational properties of a polymer chain under tension in a good solvent, a physical condition that is often realized both in single-molecule experiments and in vivo. Our findings reveal the existence of hitherto unobserved universal laws encompassing polymers with different rigidities and including the possible presence of excluded-volume effects, showing that both shape and orientation are solely determined by the force contribution to the free energy. In doing so, they also provide a simple way to retrieve these quantities from the knowledge of the force-versus-extension curve.

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

18/09/2017 - 18/09/2017Fabrication of Gold Nano-Crystal Arrays for Molecular Electronics: High Frequency Molecular Rectifiers and π-π Inter Molecular Interaction Energy

 

Abstract:  

E-beam lithography was used for versatile fabrication of sub-15 nm single-crystal gold nanoarrays at wafer-scale by the so-called dot on the fly (DOTF) technique [1]. Here DOTF and other methods are compared evidencing the limiting factors for the writing speed. Wafer-scale fabrication of such arrays with 50 nm pitch allowed XPS analysis of a ferrocenylalkyl thiol self- assembled monolayer coated gold nanoarray. We exploit these arrays as a suitable test bed for Molecular Electronics (ME) [2] and propose two studies on high frequency molecular rectifiers [3] and inter molecular Interactions [4].

 

In a first study, we demonstrate molecular diodes operating up to 17.8 GHz. Direct current and radio frequency (RF) properties were simultaneously measured with the tip of an interferometric scanning microwave microscope and S11 parameters show a diode rectification ratio of 12 dB. In a second investigation, we explore the π-π intermolecular interactions. This factor is one of the most important to optimize the transport and optical properties of organic transistors, light-emitting diodes or (bio-) molecular devices. Electrochemical measurements indicate two different phases localized on top and facets of the nanocrystals with clear intermolecular interactions and electrical current statistics on ~3000 molecular junctions confirm the theoretical prediction [5] of asymmetrical histograms due to cooperative effects.

 

References:

 

[1] J. Trasobares, F. Vaurette, M. François, H. Romijn, J-L. Codron, D. Vuillaume, D. Théron and N.

Clément. High speed e-beam lithography for gold nanoarray fabrication and use in nanotechnology. Beilstein J. Nanotechnol. 5, 1918–1925 (2014).

[2] N. Clement, G. Patriarche, K, Smaali, F. Vaurette, K. Nishiguchi, D. Troadec, A. Fujiwara, D. Vuillaume. Large array of sub-10-nm single-grain Au nanodots for use in nanotechnology. Small, 7, 2607 (2011).

[3] J. Trasobares, D. Vuillaume, D. Théron, N. Clement, A 17 GHz Molecular Rectifier, Nat.Commun. 7, 12850 (2016).

[4] J. Trasobares, J. Rech, T. Jonckeere, T. Martin, O. Aleveque, E. Levillain, V. Diez-Cabanes, Y. Olivier, J. Cornil, J.P. Nys, R. Sivakumarasamy, K. Smaali, Ph. Leclère, A. Fujiwara, D. Théron, D. Vuillaume, N. Clément. Estimation of π-π Electronic Couplings from Current Measurements. Nano Letters, 17, 3215-3224 (2017).

[5] M.G. Reuter, M.C. Hersam, T. Seideman, M.A. Ratner. Signatures of cooperative effects and transport mechanisms in conductance histograms. Nano Letters, 12, 2243-2248 (2012).

 

Más información: http://www.ifimac.uam.es/category/seminars/

 

 

 

 

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Estudios

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Síguenos en...
Congreso PASCOS 2017. Conferencia de Barry Barish, premio Princesa de Asturias de Investigación.
Simposio internacional "Rio Tinto, análogo terrestre de Marte"
18º Ciclo Seminarios Severo Ochoa CBMSO: Sandrine Bourdoulous.

Agentes y colaboradores

  • Universidad Autónoma de Madrid
  • CSIC
  • ASEYACOVI
  • ACENOMA
  • AICA
  • Centro de Microanálisis de Materiales (CMAM)
  • Centro de Investigación en Física de la Materia Condensada (IFIMAC)
  • CBMSO - Centro de Biología Molecular Severo Ochoa
  • CIAL - Centro de Investigación en Ciencias de la Alimentación
  • CNB - Centro Nacional de Biotecnología 
  • Centro de Iniciativas Emprendedoras (CIADE)
  • Cámara de Madrid
  • FEMAN
  • Fundación Universitaria Autónoma de Madrid
  • ICMAT - Instituto de Ciencias Matemáticas
  • ICMM - Instituto de Ciencia de Materiales de Madrid
  • ICP - Instituto de Catálisis y Petroquímica
  • ICV - Instituto de Cerámica y Vidrio
  • IFT - Instituto de FísicaTeórica
  • IIBM - Instituto de Investigaciones Biomédicas Alberto Sols
  • IMDEA - Alimentación
  • IMDEA - Nanociencia
  • IMM - Instituto de Microelectrónica de Madrid
  • InNorMadrid
  • Parque Científico de Madrid
  • Oficina de Transferencia de Resultados de la Investigación (OTRI) de la UAM
  • Facultad de Ciencias
  • Facultad de Ciencias Económicas y Empresariales
  • Facultad de Derecho
  • Facultad de Filosofía y Letras
  • Facultad de Medicina
  • Facultad de Formación de Profesorado y Educación
  • Facultad de Psicología
  • Escuela Politécnica Superior
Proyecto realizado con ayudas concedidas por el Ministerio de Economía y Competitividad / EXPEDIENTE: CEI10-1-0009 CEI UAM+CSIC: INNOCAMPUS 2010 Proyecto financiado por el Ministerio de Educación, Cultura y Deporte, y el Ministerio de Economía y Competitividad en el marco del Programa Campus de Excelencia Internacional/ EXPEDIENTE: CEI10-1-0009 CEI UAM+CSIC: INNOCAMPUS 2010