Hot Electrons and Hot Spins at Metal–Organic Interfaces

Arnold, Thorsten; Atxabal, Ainhoa; Parui, Subir; Hueso, Luis E.; Ortmann, Frank

doi:10.1002/adfm.201706105

Cited by 15 publications

(17 citation statements)

References 154 publications

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“…2a, c) taking into account the increase of the inelastic scattering in the base with temperature (see Fig. 2b, d, Supplementary Table 2 and Supplementary Note 1) 36 . In addition, Supplementary Fig.…”

Section: Resultsmentioning

confidence: 99%

Tuning the charge flow between Marcus regimes in an organic thin-film device

et al. 2019

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Marcus’s theory of electron transfer, initially formulated six decades ago for redox reactions in solution, is now of great importance for very diverse scientific communities. The molecular scale tunability of electronic properties renders organic semiconductor materials in principle an ideal platform to test this theory. However, the demonstration of charge transfer in different Marcus regions requires a precise control over the driving force acting on the charge carriers. Here, we make use of a three-terminal hot-electron molecular transistor, which lets us access unconventional transport regimes. Thanks to the control of the injection energy of hot carriers in the molecular thin film we induce an effective negative differential resistance state that is a direct consequence of the Marcus Inverted Region.

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Section: Resultsmentioning

confidence: 99%

Tuning the charge flow between Marcus regimes in an organic thin-film device

et al. 2019

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“…[ 3,4 ] In this case, only spin‐up polarized states exist in LSMO thin film unlike FM metals according to the spin polarization simulation formula: (N ↑ ‐N ↓ )/(N ↑ +N ↓ ) × 100% (N ↑ stands for spin‐up density, N ↓ represents spin‐down density). [ 68 ] From this perspective, analyzing negative MR resource via such half‐metal spin polarizer is a better choice. We first measured the MR response of the device fabricated by employing DCB solvent.…”

Section: Resultsmentioning

confidence: 99%

Negative Magnetoresistance Behavior in Polymer Spin Valves Based on Donor−Acceptor Conjugated Molecules

Zheng

Xiang

Zheng

et al. 2020

Adv Materials Inter

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devices, namely ferromagnetic (FM) spin injectors and detectors and non-ferromagnetic organic medium. When evaluating OSV device performance, magnetoresistance (MR) behavior is an important criterion. [7-11] Undoubtedly, decent MR value is strongly expected for its close proof to long distance spin-conserved transport. Continuous efforts of seeking suitable spin polarizer and transport media fueled the development of OSVs during the past decade. [2-4,11-14] On the other hand, debate on MR signal has never ceased since the first report on organic giant magnetoresistance by Xiong. [7] In general, MR response in a prototype OSV device is considered to be positive, namely device resistance under magnetization antiparallel states is larger than that of parallel states. However, negative (abnormal) MR response in OSVs is increasingly discovered thus must not be fortuity. Consequently, distinguishing the working mechanisms of the negative MR signals becomes an important component of organic spintronics. To date, there are several viewpoints to explain this abnormal spin response: 1) Negative polarization is the most representative also the earliest explanation which is primarily extracted from Julliere tunneling formula. [15-17] That is when spin injector is positively (negatively) polarized, while spin detector is negatively (positively) polarized, the MR behavior is negative. However, such explanation is invalid when injecting Organic spin valves (OSVs) have become an essential building block of next-generation memory devices which focus on spin degree of transporting carriers. Meanwhile, negative magnetoresistance (MR) effect in the OSV devices is increasingly observed which deserves further exploration for the rich spin physics behind. In this work, the negative MR response in ferromagnetic (FM) metal-based OSVs using donor−acceptor (D−A) conjugated polymer based on the naphthalenediimide units as a spacer material is observed. The negative MR effect does not result from negative polarization at spin injection and detection interface as well as tunneling anisotropic magnetoresistance effect, but from the spin transport inside the D−A polymer spacer. Even the stacking sequence of the spin injection and detection electrodes is reversed or changed the polymer coating solvents, the D−A polymer contributed negative MR response still can be observed. For further identifying negative MR origin, the bottom FM metal polarizer is replaced into high-polarization La 0.7 Sr 0.3 MnO 3 thin film, negative MR feature is well reproduced. Based on these points, it is deduced that the spin-orientation reversal inside D−A polymer spacer is the ultimate reason for such negative MR response. The filtering-like spin reversal activity is also in positive proportion to intermolecular interaction.

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“…Here, hot electrons will be attenuated in the metallic base, which can be described by formula (2). 19 sðE;…”

Section: Device Structure and Working Principle Of Hetmentioning

confidence: 99%

“…In recent years, hot electron transistors (HETs) have been developed to determine intrinsic energy levels and perform an in-depth analysis of the energy level alignment. 19 In this study, a molecule-based device comprising a metallic base, molecular semiconductor, and metallic collector is placed in a HET. The in-situ detection of energy levels and interfacial energy level alignments has been realized for the first time.…”

Section: Introductionmentioning

confidence: 99%