Solmar Varela

Solmar Varela
Technische Universität Dresden | TUD · Institute of Materials Science

PhD Physics '16
Eleonore Trefftz Visiting Professor at Chair of Materials Science and Nanotechnology. TU Dresden

About

27
Publications
6,243
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388
Citations
Introduction
My work is focused in the analytical study of electron and spin transport in organic molecules (Molecular Spintronics).
Additional affiliations
November 2017 - present
Yachay Tech
Position
  • Lecturer
April 2017 - November 2017
Yachay Tech
Position
  • Lecturer
February 2011 - October 2013
Venezuelan Institute for Scientific Research
Position
  • Researcher in training
Education
February 2010 - June 2016
Central University of Venezuela
Field of study
  • Physics
October 2004 - November 2009

Publications

Publications (27)
Article
Full-text available
We analyze single scattering of unpolarized photoelectrons through a monolayer of chiral molecules modeled by a continuous hardcore helix and spin-orbit coupling. The molecular helix is represented by an optical contact potential containing a non-hermitian component describing inelastic events. Transmitted photoelectrons are transversely polarized...
Article
Full-text available
We derive a detailed analytical tight-binding (TB) model for a double helix emulating DNA with one type of nucleotide pair and a single oriented π orbital per base. The TB model incorporates both kinetic and intrinsic spin-orbit (ISO) contributions as well as Rashba-type interactions coupled to an external electric field along the axis of the doubl...
Preprint
Full-text available
Chiral structures, breaking spatial inversion symmetry, exhibit non-zero chiroptical activity (COA) due to the interaction between their electric and magnetic responses under external electromagnetic fields, an effect that is otherwise absent in achiral systems. Non-magnetic chiral structures also exhibit Chiral Induced Spin Selectivity (CISS), whe...
Article
We address the electron-spin-phonon coupling in an effective model Hamiltonian for DNA to assess its role in spin transfer involved in the Chiral-Induced Spin Selectivity (CISS) effect. The envelope function approach is used to describe semiclassical electron transfer in a tight-binding model of DNA at half filling in the presence of intrinsic spin...
Article
Full-text available
Basic questions on the nature of spin polarization in two terminal systems and the way in which decoherence breaks Time-Reversal Symmetry (TRS) are analyzed. We exactly solve several one-dimensional models of tunneling electrons and show the interplay of spin precession and decay of the wavefunction in either a U(1) U ( 1 ) magnetic field or an eff...
Preprint
Full-text available
Basic questions on the nature of spin polarization in two terminal systems and the way in which decoherence breaks Time-Reversal Symmetry (TRS) are analyzed. We exactly solve several one-dimensional models of tunneling electrons and show the interplay of spin precession and decay of the wavefunction in either a U(1) magnetic field or an effective S...
Article
Full-text available
There is increasing interest in the study of chiral degrees of freedom occurring in matter and in electromagnetic fields. Opportunities in quantum sciences will likely exploit two main areas that are the focus of this Review: (1) recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterial...
Article
Full-text available
The spin activity in macromolecules such as DNA and oligopeptides, in the context of the Chiral Induced Spin Selectivity (CISS) has been proposed to be due to the atomic Spin-Orbit Coupling (SOC) and the associated chiral symmetry of the structures. This coupling, associated with carbon, nitrogen, and oxygen atoms in biological molecules, albeit sm...
Preprint
Full-text available
The spin activity in macromolecules such as DNA and oligopeptides, in the context of the Chiral Induced Spin Selectivity (CISS) has been proposed to be due to the atomic Spin-Orbit Coupling (SOC) and the associated chiral symmetry of the structures. This coupling, associated with carbon, nitrogen and oxygen atoms in biological molecules, albeit sma...
Preprint
Full-text available
The comment by O. Entin-Wohlman, A. Aharony, and Y. Utsumi, on our paper S. Varela, I. Zambrano, B. Berche, V. Mujica, and E. Medina, Phys. Rev. B 101, 241410(R) (2020) makes a few points related to the validity of our model, especially in the light of the interpretation of Bardarson's theorem: "in the presence of time reversal symmetry and for hal...
Article
We analyze the influence of electron-phonon (e-ph) interaction in a model for electron transfer (ET) processes in DNA in terms of the envelope function approach for spinless electrons. We are specifically concerned with the effect of e-ph interaction on the coherence of the ET process, and how to model the interaction of DNA with phonon reservoirs...
Preprint
Full-text available
The interest in chiral degrees of freedom occurring in matter and in electromagnetic fields is experiencing a renaissance driven by recent observations of the chiral-induced spin selectivity (CISS) effect in chiral molecules and engineered nanomaterials. The CISS effect underpins the fact that charge transport through nanoscopic chiral structures h...
Article
Full-text available
Recently experiments have shown very significant spin activity in biological molecules such as DNA, proteins, oligopeptides, and aminoacids. Such molecules have in common their chiral structure, time reversal symmetry and the absence of magnetic exchange interactions. The spin activity is then assumed to be due to either the intrinsic spin-orbit (S...
Article
Full-text available
Electron transfer (ET) in biological molecules, such as peptides and proteins, consists of electrons moving between well-defined localized states (donors to acceptors) through a tunneling process. Here, we present an analytical model for ET by tunneling in DNA in the presence of spin-orbit (SO) interaction to produce a strong spin asymmetry with th...
Preprint
Full-text available
Recently experiments have shown very significant spin activity in biological molecules such as DNA, proteins, oligopeptides and aminoacids. Such molecules have in common their chiral structure, time reversal symmetry and the absence of magnetic exchange interactions. The spin activity is then assumed to be due to either the pure Spin-orbit (SO) int...
Article
The chiral-induced spin selectivity (CISS) effect, which describes the spin-filtering ability of diamagnetic structures like DNA or peptides having chiral symmetry, has emerged in the past years as the central mechanism behind a number of important phenomena, like long-range biological electron transfer, enantiospecific electrocatalysis, and molecu...
Preprint
Electron transfer (ET) in biological molecules such as peptides and proteins consists of electrons moving between well defined localized states (donors to acceptors) through a tunneling process. Here we present an analytical model for ET by tunneling in DNA, in the presence of Spin-Orbit (SO) interaction, to produce a strong spin asymmetry with the...
Preprint
Full-text available
We present an analytical model for the role of hydrogen bonding on the spin-orbit coupling of model DNA molecule. Here we analyze in detail the electric fields due to the polarization of the Hydrogen bond on the DNA base pairs and derive, within tight binding analytical band folding approach, an intrinsic Rashba coupling which should dictate the or...
Article
Full-text available
We present an analytical model for the role of hydrogen bonding on the spin-orbit coupling of model DNA molecule. Here we analyze in detail the electric fields due to the polarization of the Hydrogen bond on the DNA base pairs and derive, within tight binding analytical band folding approach, an intrinsic Rashba coupling which should dictate the or...
Preprint
An intriguing phenomenon has emerged in the past years showing considerable promise for new spintronic devices, catalysis, and for biological electron transfer: the chiral- induced spin selectivity (CISS) effect, which describes the spin-filtering ability of diamagnetic helical structures like DNA or peptides having chiral symmetry. The effect is a...
Presentation
Full-text available
Mechanical Deformations in Organic Molecules
Presentation
Full-text available
We consider molecular straining as a probe to understand the mobility and spin active features of complex molecules. The strength of the spin-orbit interaction relevant to transport in a low dimensional structure depends critically on the relative geometrical arrangement of current-carrying orbitals. Understanding the origin of the enhanced spin-or...
Article
Full-text available
We consider molecular straining as a probe to understand the mobility and spin active features of complex molecules. The strength of the spin-orbit interaction relevant to transport in a low dimensional structure depends critically on the relative geometrical arrangement of current-carrying orbitals. Understanding the origin of the enhanced spin-or...
Article
Full-text available
The strength of the spin-orbit interaction relevant to transport in a low dimensional structure depends critically on the relative geometrical arrangement of current carrying orbitals. Recent tight-binding orbital models for spin transport in DNA-like molecules, have surmised that the band spin-orbit coupling arises from the particular angular rela...
Article
Full-text available
Resumen En la asignatura Física General I de la Licenciatura en Física y en Matemática de la UCV, el sistema de enseñanza empleado expone a los estudiantes a grandes cantidades de información y contenidos en el aula de clases, donde ocurre la interacción estudiante-profesor. Se está promoviendo la incorporación de las Tecnologías de la Información...
Thesis
Full-text available
En el régimen localizado, se derivó un modelo tight-binding (TB) analítico detallado para una molécula de doble hélice de ADN, con un tipo de par de nucleótidos y orbitales pz orientados en las bases. El modelo incorpora energía cinética y contribuciones SO intrínseca (ISO) y de tipo Rashba acoplado a un campo eléctrico externo a lo largo del eje d...

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