Query: Spin Filtering through Chiral Molecules on Semiconductors

Candidate papers:

author_names: Tianhan Liu

Longqian Hu

Eric J Lochner

Xiao-Lei Wang

Hailong Wang

Gang Shi

Fan Gao

Honglei Feng

Yongqing Li

Jianhua Zhao

Peng Xiong
title: Spin Filtering through Chiral Molecules on Semiconductors
year: 2019

abstract: Recent experiments have demonstrated that the electron transmission yield through chiral molecules depends on the electron spin orientation. This phenomenon has been termed the chiral induced spin selectivity (CISS) effect, and it provides a challenge to theory and promise for organic molecule based spintronic devices. This article reviews recent developments in our understanding of CISS. Different theoretical models have been used to describe the effect; however, they all presume an unusually large spin orbit coupling in chiral molecules for the effect to display the magnitudes seen in experiments. A simplified model for an electron's transport through a chiral potential suggests that these large couplings can be manifested. Techniques for measuring spin selective electron transport through molecules are overviewed, and some examples of recent experiments are described. Finally, we present results obtained by studying several systems, and we describe the possible application of the CISS effect for memory devices.
author_names: Ron Naaman

David H Waldeck
title: Spintronics and chirality: spin selectivity in electron transport through chiral molecules.
venue: Annual review of physical chemistry
year: 2015

abstract: Density of States function, g(E) Fermi Dirac Distribution function, f(E) Distribution Function and Fermi Energy Equilibrium Distribution of Electrons and Holes n0 and p0 Equation Intrinsic carrier concentration Fermi level for Intrinsic Semiconductor Extrinsic Semiconductor Position of the Fermi Level of the Extrinsic Semiconductor Non Degenerated Semiconductor Variation of EF with Doping Concentration and with Temperature Compensated Semiconductor Statistics of donors and acceptors Formula to remember Question Bank Solved problems Assignment
author_names: S M Sze
title: PHYSICS OF SEMICONDUCTOR DEVICES
year: 2007

abstract: Understanding the origin of chirality in nature has been an active area of research since the time of Pasteur. In this chapter we examine one possible route by which this asymmetry could have arisen, namely chiral specific chemistry induced by spin polarized electrons. The various sources of spin polarized electrons (parity violation, photoemission, and secondary processes) are discussed. Experiments aimed at exploring these interactions are reviewed starting with those based on the Vester Ulbricht hypothesis through recent studies of spin polarized secondary electrons from a magnetic substrate. We will conclude with a discussion of possible new avenues of research that could impact this area.
author_names: Richard A Rosenberg
title: Spin polarized electron induced asymmetric reactions in chiral molecules.
venue: Topics in current chemistry
year: 2011

abstract: Electron transmission through chiral molecules induced by circularly polarized light can be very different for mirror image structures, a peculiar fact given that the electronic energy spectra of the systems are identical. We propose that this asymmetry as large as 10% for resonant transport arises from different dynamical responses of the mirrored structures to coherent excitation. This behavior is described in the context of a general novel phenomenon of current transfer (transfer of charge with its momentum information) and accounts for the observed asymmetry and its dependence on structure.
author_names: Spiros S Skourtis

David N Beratan

Ron Naaman

Abraham Nitzan

David H Waldeck
title: Chiral control of electron transmission through molecules.
venue: Physical review letters
year: 2008

abstract: The functionality of many biological systems depends on reliable electron transfer with minimal heating. Unlike man made electric circuits, nature realizes electron transport via insulating chiral molecules. Here we include spin into the analysis of tunneling through these molecules, and demonstrate its importance for efficient transport. We show that the helical geometry induces robust spin filtering accompanied by, and intimately related to, strongly enhanced transmission. Thus, we resolve two key questions posed by transport measurements through organic molecules, demonstrating their common origin.
author_names: Karen Michaeli

Ron Naaman
title: Origin of Spin Dependent Tunneling Through Chiral Molecules
venue: The Journal of Physical Chemistry C
year: 2019

abstract: The ultimate aim of any detection method is to achieve such a level of sensitivity that individual quanta of a measured entity can be resolved. In the case of chemical sensors, the quantum is one atom or molecule. Such resolution has so far been beyond the reach of any detection technique, including solid state gas sensors hailed for their exceptional sensitivity. The fundamental reason limiting the resolution of such sensors is fluctuations due to thermal motion of charges and defects, which lead to intrinsic noise exceeding the sought after signal from individual molecules, usually by many orders of magnitude. Here, we show that micrometre size sensors made from graphene are capable of detecting individual events when a gas molecule attaches to or detaches from graphene's surface. The adsorbed molecules change the local carrier concentration in graphene one by one electron, which leads to step like changes in resistance. The achieved sensitivity is due to the fact that graphene is an exceptionally low noise material electronically, which makes it a promising candidate not only for chemical detectors but also for other applications where local probes sensitive to external charge, magnetic field or mechanical strain are required.
author_names: Fred Schedin

Andre K Geim

S V Morozov

Ernie W Hill

Peter Blake

Mikhail I Katsnelson

Kostya S Novoselov
title: Detection of individual gas molecules adsorbed on graphene.
venue: Nature materials
year: 2007

abstract: Conspectus Molecular spintronics (spin electronics) which aims to exploit both the spin degree of freedom and the electron charge in molecular devices, has recently received massive attention. Our recent experiments on molecular spintronics employ chiral molecules which have the unexpected property of acting as spin filters, by way of an effect we call "chiral induced spin selectivity" (CISS) In this Account, we discuss new types of spin dependent electrochemistry measurements and their use to probe the spin dependent charge transport properties of nonmagnetic chiral conductive polymers and biomolecules, such as oligopeptides, L/D cysteine, cytochrome c, bacteriorhodopsin (bR) and oligopeptide CdSe nanoparticles (NPs) hybrid structures. Spin dependent electrochemical measurements were carried out by employing ferromagnetic electrodes modified with chiral molecules used as the working electrode. Redox probes were used either in solution or when directly attached to the ferromagnetic electrodes. During the electrochemical measurements, the ferromagnetic electrode was magnetized either with its magnetic moment pointing "UP" or "DOWN" using a permanent magnet (H 0.5 T) placed underneath the chemically modified ferromagnetic electrodes. The spin polarization of the current was found to be in the range of 5 30% even in the case of small chiral molecules. Chiral films of the l and d cysteine tethered with a redox active dye, toludin blue O, show spin polarizarion that depends on the chirality. Because the nickel electrodes are susceptible to corrosion, we explored the effect of coating them with a thin gold overlayer. The effect of the gold layer on the spin polarization of the electrons ejected from the electrode was investigated. In addition, the role of the structure of the protein on the spin selective transport was also studied as a function of bias voltage and the effect of protein denaturation was revealed. In addition to "dark" measurements, we also describe photoelectrochemical measurements in which light is used to affect the spin selective electron transport through the chiral molecules. We describe how the excitation of a chromophore (such as CdSe nanoparticles) which is attached to a chiral working electrode, can flip the preferred spin orientation of the photocurrent, when measured under the identical conditions. Thus, chirality induced spin polarization, when combined with light and magnetic field effects, opens new avenues for the study of the spin transport properties of chiral molecules and biomolecules and for creating new types of spintronic devices in which light and molecular chirality provide new functions and properties.
author_names: Prakash Chandra Mondal

Claudio Fontanesi

David H Waldeck

Ron Naaman
title: Spin Dependent Transport through Chiral Molecules Studied by Spin Dependent Electrochemistry
venue: Accounts of chemical research
year: 2016

abstract: The electron's spin is essential to the stability of matter, and control over the spin opens up avenues for manipulating the properties of molecules and materials. The Pauli exclusion principle requires that two electrons in a single spatial eigenstate have opposite spins, and this fact dictates basic features of atomic states and chemical bond formation. The energy associated with interacting electron clouds changes with their relative spin orientation, and by manipulating the spin directions, one can guide chemical transformations. However, controlling the relative spin orientation of electrons located on two reactants (atoms, molecules or surfaces) has proved challenging. Recent developments based on the chiral induced spin selectivity (CISS) effect show that the spin orientation is linked to molecular symmetry and can be controlled in ways not previously imagined. For example, the combination of chiral molecules and electron spin opens up a new approach to (enantio)selective chemistry. This Review describes the theoretical concepts underlying the CISS effect and illustrates its importance by discussing some of its manifestations in chemistry, biology and physics. Specifically, we discuss how the CISS effect allows for efficient long range electron transfer in chiral molecules and how it affects biorecognition processes. Several applications of the effect are presented, and the importance of controlling relative spin orientations in multi electron processes, such as electrochemical water splitting, is emphasized. We describe the enantiospecific interaction between ferromagnetic substrates and chiral molecules and how it enables the separation of enantiomers with ferromagnets. Lastly, we discuss the relevance of CISS effects to biological electron transfer, enantioselectivity and CISS based spintronics applications.Chiral molecules can filter electrons according to their spin. This chiral induced spin selectivity (CISS) effect can have important applications, such as in spintronics and in enantioseparation. This Review describes the CISS effect, its mechanism and its fascinating applications.
author_names: Ron Naaman

Yossi Paltiel

David H Waldeck
title: Chiral molecules and the electron spin
venue: Nature Reviews Chemistry
year: 2019

abstract: Recent experiments have demonstrated the efficacy of chiral helically shaped molecules in polarizing the scattered electron spin, an effect termed as chiral induced spin selectivity (CISS) Here we solve a simple tight binding model for electron transport through a single helical molecule, with spin orbit interactions on the bonds along the helix. Quantum interference is introduced via additional electron hopping between neighboring sites in the direction of the helix axis. When the helix is connected to two one dimensional single mode leads, time reversal symmetry prevents spin polarization of the outgoing electrons. One possible way to retrieve such a polarization is to allow leakage of electrons from the helix to the environment, via additional outgoing leads. Technically, the leakage generates complex site self energies, which break unitarity. As a result, the electron waves in the helix become evanescent, with different decay lengths for different spin polarizations, yielding a net spin polarization of the outgoing electrons, which increases with the length of the helix (as observed experimentally) A maximal polarization can be measured at a finite angle away from the helix axis.
author_names: Shlomi Matityahu

Yasuhiro Utsumi

Amnon Aharony

O Entin-wohlman

C A Balseiro
title: Spin dependent transport through a chiral molecule in the presence of spin orbit interaction and nonunitary effects
year: 2016