Article
Chemistry, Multidisciplinary
Jiang Yao, Peter J. Wagner, Yunpeng Xia, Gregory Czap, W. Ho
Summary: This article introduces the study of DC current generation and its connection with inelastic electron tunneling spectroscopy and microscopy. The research found that although both techniques involve nonlinear features, there are significant differences in line shape analysis, which provides two complementary techniques for probing nanoscale systems.
Article
Chemistry, Multidisciplinary
Siyu Chen, Wenlu Shi, W. Ho
Summary: We demonstrate rectification spectroscopy (RS) for single molecules using continuous-wave terahertz (CW THz) radiation at the tunneling junction of a scanning tunneling microscope (STM) at 8 K. CW THz-RS offers a new technique for studying single-molecule vibrational and magnetic excitation spectroscopy, alongside inelastic electron tunneling spectroscopy (IETS). By comparing IETS and THz RS, we find that CW THz induces a sinusoidal bias modulation with an amplitude that is linearly dependent on the THz far-field amplitude. This THz-induced bias modulation amplitude appears to be sensitive to the alignment of the THz beam but insensitive to changes in the tunneling gap smaller than the THz wavelength.
Review
Engineering, Electrical & Electronic
Youngsang Kim, Soon W. Chang
Summary: Inelastic electron tunneling spectroscopy (IETS) is a critical measurement technique for scrutinizing material structures and molecular compositions in metal-oxide-semiconductor (MOS) structures and molecular devices, providing important information regarding bond structures, impurities, defects, traps, molecular conformation, isomerization, and contact geometry.
IEEE TRANSACTIONS ON ELECTRON DEVICES
(2021)
Review
Chemistry, Multidisciplinary
Shenghan Zhou, Ke Chen, Matthew Thomas Cole, Zhenjun Li, Mo Li, Jun Chen, Christoph Lienau, Chi Li, Qing Dai
Summary: The search for higher frequency information processing has led to intense research in micro, nano, and optoelectronics, with electron tunneling devices offering significantly faster response times compared to conventional semiconductor devices. This enhanced performance is driving the reimagination of traditional electronic devices and the emergence of new lightwave electronics. The current state-of-the-art, challenges, and opportunities in electron tunneling devices are reviewed, alongside potential future research directions in this rapidly advancing field.
ADVANCED MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Samuel L. Rudge, Yaling Ke, Michael Thoss
Summary: This article introduces an approach to calculating current-induced forces in charge transport through nanosystems. By starting from the fully quantum mechanical hierarchical equations of motion formalism, a classical Langevin equation of motion for the vibrational dynamics influenced by current-induced forces is derived through a timescale separation between electronic and vibrational degrees of freedom, such as electronic friction. The numerical exactness of the hierarchical equations of motion approach allows for the investigation of transport scenarios with strong intrasystem and system-environment interactions. As a demonstration, the electronic friction of three example systems is calculated and analyzed: a single electronic level coupled to one classical vibrational mode, an Anderson impurity model coupled to one classical vibrational mode, and a single electronic level coupled to both a classical and quantum vibrational mode.
Article
Chemistry, Multidisciplinary
Alexander Mehler, Nicolas Neel, Elena Voloshina, Yuriy Dedkov, Jorg Kroger
Summary: The study demonstrates the growth of graphene on h-BN through thermal decomposition and catalytic assistance of metal substrates, as well as the epitaxial growth of h-BN on Pt(111). Different honeycomb structures of graphene on h-BN and the observation of distinct superstructures at small probe-surface distances are highlighted in this study.
Article
Nanoscience & Nanotechnology
Yiyun Zhang, Dominic Lepage, Yiming Feng, Sihan Zhao, Hongsheng Chen, Haoliang Qian
Summary: Tunnel nanojunctions based on inelastic electron tunneling (IET) have been proposed as breakthroughs for ultra-fast integrated light sources, but the weak photon-emission power and limited efficiency due to elastic tunneling have hindered their practical applications. Resonant tunneling has been suggested as a solution, but the contradiction between high photon-emission efficiency and power has remained unsatisfactory. This work introduces a novel approach using multiple metallic quantum wells to achieve stronger resonant tunneling enhancement, enabling the internal quantum efficiency to reach approximately 1 and photon-emission power to reach approximately 0.8 μW/μm², bringing practical implementation of IET-based sources one step closer to reality.
Article
Multidisciplinary Sciences
Shankar Kesarwani, Shobhna Misra, Dipankar Saha, Maria Luisa Della Rocca, Indrajit Roy, Swaroop Ganguly, Ashutosh Mahajan
Summary: In this paper, a noise-filtering algorithm based on Tikhonov Regularization is proposed for extracting IET spectra from measured DC I-V curves. By applying this algorithm to experimental data, it is demonstrated that the computed derivatives match well with the measured values, and the computed IET spectral peaks correlate with the experimental results.
SCIENTIFIC REPORTS
(2022)
Article
Chemistry, Multidisciplinary
Eugenia Pyurbeeva, Chunwei Hsu, David Vogel, Christina Wegeberg, Marcel Mayor, Herre van der Zant, Jan A. Mol, Pascal Gehring
Summary: Single molecules can reveal the presence of microscopic electron transfer dynamics through entropy measurement, and thermoelectric measurement can uncover spin transitions in the redox states of a molecule in a magnetic field. The power of thermoelectric measurements lies in determining the difference in configurational entropy between redox states of a nanoscale system without prior assumptions about its structure or dynamics.
Article
Materials Science, Multidisciplinary
Lin Huang, Yu-Jia Zeng, Dan Wu, Nan-Nan Luo, Ye-Xin Feng, Zhi-Qiang Fan, Li-Ming Tang, Ke-Qiu Chen
Summary: High tunneling magnetoresistance (TMR) can be achieved in molecular junctions based on Co-Salophene symmetric/asymmetric dimers, with nearly 100% spin-injection efficiency (SIE) in parallel spin configuration. The TMR properties are closely related to molecular symmetry, reaching up to 4600% and 2200% for symmetric and asymmetric molecular junctions, respectively.
JOURNAL OF MATERIALS CHEMISTRY C
(2021)
Article
Chemistry, Multidisciplinary
Anna Kuzmina, Markus Parzefall, Patrick Back, Takashi Taniguchi, Kenji Watanabe, Achint Jain, Lukas Novotny
Summary: By controlled stacking of graphene layers, the limitation of single-layer graphene as a material for light-emitting devices has been overcome, enabling twist-controlled resonant light emission. Experimental findings show light emission irrespective of the crystallographic alignment between the graphene electrodes, with a spectrally tunable resonant peak in the near-infrared range.
Article
Chemistry, Multidisciplinary
Shaoqing Du, Yoshifumi Hashikawa, Haruka Ito, Katsushi Hashimoto, Yasujiro Murata, Yoshiro Hirayama, Kazuhiko Hirakawa
Summary: In this study, electron transport through H2O@C-60 single molecule transistors (SMTs) was investigated, revealing the presence of multiple tunneling-induced excited states below 30 meV. Terahertz (THz) photocurrent spectroscopy on H2O@C-60 SMTs confirmed the same excitations, with quantum rotational excitations of the water molecule observed below 10 meV. The simultaneous observation of quantum rotational excitations of both para- and ortho-water molecule for a single water molecule suggests a rapid fluctuation between the two states due to interaction with conducting electrons.
Article
Chemistry, Multidisciplinary
Prosper Ngabonziza, Yi Wang, Peter A. van Aken, Joachim Maier, Jochen Mannhart
Summary: Researchers have developed high-temperature-stable tunnel junctions for inelastic tunneling spectroscopy studies above room temperature. By analyzing the vibrational modes of O-H bonds in BaZrO3-based heterostructures, they achieved proton detection with a spectral resolution of 20 meV at 400 K, overturning previous predictions. This breakthrough enables high-temperature tunneling spectroscopy of ion conductors, making it a novel and valuable analytical tool for solid-state ionics.
ADVANCED MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Daniel P. Harrison, Robin Grotjahn, Masnun Naher, Seyed M. B. H. Ghazvini, Daniel M. Mazzucato, Marcus Korb, Stephen A. Moggach, Colin Lambert, Martin Kaupp, Paul J. Low
Summary: The study shows that the 4-OMe substituent in [{Cp*(dppe)RuC equivalent to C}(2)(mu-1,3-C6H4)](+) mixed-valence complex enhances the ground state electron delocalization and intensity of the IVCT transition. The experimental results and vibrational frequency and TDDFT calculations confirm the findings.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2022)
Article
Chemistry, Multidisciplinary
N. Krane, E. Turco, A. Bernhardt, D. Jacob, G. Gandus, D. Passerone, M. Luisier, M. Juricek, R. Fasel, J. Fernandez-Rossier, P. Ruffieux
Summary: In this study, we report the successful synthesis of Phenalenyl dimer through a combination of in-solution synthesis and on-surface activation, and characterize its properties using inelastic electron tunneling spectroscopy (IETS). The results show significant renormalization of Phenalenyl due to exchange with Au(111) electrons and explain the position-dependent bias asymmetry and activation of kinetic interphenalenyl exchange. This study paves the way for the bottom-up synthesis of S = 1/2 spin-lattices with large exchange interactions.
Article
Chemistry, Multidisciplinary
Yaping Zang, E-Dean Fung, Tianren Fu, Suman Ray, Marc H. Garner, Anders Borges, Michael L. Steigerwald, Satish Patil, Gemma Solomon, Latha Venkataraman
Summary: The structural changes in a DPP molecule induced by charge transport at a high bias increase the average nonresonant conductance of Au-DPP-Au junctions and lead to planarization of the molecular backbone. This conformational planarization is assisted by thermally activated junction reorganization and only occurs under specific electronic conditions.
Article
Materials Science, Multidisciplinary
Daniele Barettin, Alessandro Pecchia, Matthias Auf der Maur, Aldo Di Carlo, Benny Lassen, Morten Willatzen
Summary: This study compares the (k) over right arrow . (p) over right arrow and tight-binding methods for the analysis of InAs/GaAs quantum dot bandstructures based on a fully coupled computation of electromechanical effects. While the Valence Force Field algorithm in the tight-binding method allows direct identification of internal strain impacts, the lack of consideration for crystal structure details in the (k) over right arrow . (p) over right arrow formalism leads to differences in the symmetry of probability densities. Including piezoelectric field effects in the (k) over right arrow . (p) over right arrow method restores correct symmetry in the model, in agreement with the tight-binding method.
COMPUTATIONAL MATERIALS SCIENCE
(2021)
Article
Chemistry, Physical
William Bro-Jorgensen, Marc H. Garner, Gemma C. Solomon
Summary: The study introduces a method to calculate the helical curvature of linear carbon molecules' frontier molecular orbitals, providing a powerful way to quantify helical nature that can be applied to various types of carbon molecules. The results show that this method can accurately assess the helical properties of different types of molecules, paving the way for further research on how helicality affects molecular properties.
JOURNAL OF PHYSICAL CHEMISTRY A
(2021)
Article
Chemistry, Multidisciplinary
Zhen Tong, Alessandro Pecchia, ChiYung Yam, Traian Dumitrica, Thomas Frauenheim
Summary: The study finds that even ultra-narrow and aligned graphene grain boundaries (GBs) can significantly reduce the phononic thermal conductivity, due to the presence of linear GBs with pentagon-heptagon dislocations. The reduction in phononic thermal conductivity is attributed to the reflective nature of the periodic GB strain field, causing anharmonic phonon-phonon scattering. The non-monotonic relationship with dislocation density of phononic thermal conductivity uncovered in this study can help in identifying GB structures that can maintain the integrity of phononic transport.
Article
Chemistry, Multidisciplinary
Zhen Tong, Alessandro Pecchia, ChiYung Yam, Hua Bao, Traian Dumitrica, Thomas Frauenheim
Summary: The study reveals that beryllonitrene, a newly synthesized layered material, exhibits anisotropic thermal and electrical transport properties. The in-plane phonon thermal conductivity is dominated by flexural acoustic modes, while the electron thermal conductivity shows nonmonotonic variations with carrier density.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Chemistry, Physical
Alessia Di Vito, Alessandro Pecchia, Matthias Auf der Maur, Valerio Campanari, Faustino Martelli, Aldo Di Carlo
Summary: The study of MAPbI(3) phase transitions using temperature-dependent optical spectroscopy has attracted significant attention. Investigations on the tetragonal-orthorhombic transition reveal the presence of tetragonal nanodomains and segregations, with theoretical analysis showing that phase nanosegregation explains low-energy features in the PL spectra of MAPbI(3).
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Zhen Tong, Alessandro Pecchia, ChiYung Yam, Liujiang Zhou, Traian Dumitrica, Thomas Frauenheim
Summary: Beryllium polynitride (BeN4), synthesized under high-pressure conditions, exhibits an anisotropic lattice structure and thermal conductivity. The bonding anisotropy and bonding anharmonicity contribute to the anisotropic behavior in both phononic and electronic components of its thermal conductivity. The pressure-driven evolution of the interlayer bonding also plays a significant role in the interlayer thermal conductivity.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2022)
Correction
Chemistry, Physical
B. Hourahine, B. Aradi, V. Blum, F. Bonafe, A. Buccheri, C. Camacho, C. Cevallos, M. Y. Deshaye, T. Dumitrica, A. Dominguez, S. Ehlert, M. Elstner, T. van der Heide, J. Hermann, S. Irle, J. Jakowski, J. J. Kranz, C. Koehler, T. Kowalczyk, T. Kubar, I. S. Lee, V. Lutsker, R. J. Maurer, S. K. Min, I. Mitchell, C. Negre, T. A. Niehaus, A. M. N. Niklasson, A. J. Page, A. Pecchia, G. Penazzi, M. P. Persson, J. Rezac, C. G. Sanchez, M. Sternberg, M. Stohr, F. Stuckenberg, A. Tkatchenko, V. W. -Z. Yu, T. Frauenheim
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Zhen Tong, Yatian Zhang, Alessandro Pecchia, ChiYung Yam, Liujiang Zhou, Traian Dumitrica, Thomas Frauenheim
Summary: Using a thermal transport model based on density functional theory, researchers found that the recently synthesized nitride perovskite LaWN3 has strong anharmonic lattice dynamics, resulting in low lattice thermal conductivity and a non-standard temperature-dependent thermal conductivity. At high temperatures, the heat carrying phonons show dual particle-wave behavior, including vibrations tied to the N atoms. While the room temperature heat transport is mainly particle-like, there is also a significant wave-like phonon tunneling effect, contributing to a glass-like heat transport. The low lattice thermal conductivity and weak temperature dependence suggest potential applications in energy technology.
Article
Chemistry, Multidisciplinary
Daniele Barettin, Alexei V. Sakharov, Andrey F. Tsatsulnikov, Andrey E. Nikolaev, Alessandro Pecchia, Matthias Auf Der Maur, Sergey Yu. Karpov, Nikolay Cherkashin
Summary: This article investigates a possible solution for high-efficiency visible light-emitting diodes (LEDs) using InGaN-quantum-dot-based active regions. Numerical simulations are conducted on a single InGaN island with a size of ten nanometers and nonuniform indium content distribution, which is restored from an experimental image. Various two- and three-dimensional models of the quantum dot are derived, and different calculations and predictions are performed. The impact of InGaN composition fluctuations on the ground-state electron and hole wave functions and quantum dot emission spectrum is analyzed in detail. The applicability of various simulation approaches is assessed by comparing the predicted spectrum with the experimental one.
Article
Chemistry, Multidisciplinary
Yatian Zhang, Zhen Tong, Alessandro Pecchia, ChiYung Yam, Traian Dumitrica, Thomas Frauenheim
Summary: The thermal transport characteristics of monolayer trigonal prismatic tantalum disulfide were investigated using first-principles calculations and the Boltzmann transport equation. It was found that four-phonon scattering and phonon-electron scattering significantly reduced the thermal conductivity. The study also revealed differences in the electronic thermal conductivity estimation and provided new insights into the physical mechanisms of thermal transport in metallic 2D systems.
Review
Chemistry, Multidisciplinary
William Bro-Jorgensen, Joseph M. Hamill, Rasmus Bro, Gemma C. Solomon
Summary: This tutorial review describes the crucial aspects of applying machine learning to help users avoid common pitfalls. Examples based on single-molecule electron transport experiments demonstrate the application of machine learning and highlight the importance of careful application. The concepts explored are also applicable in other fields with similar data.
CHEMICAL SOCIETY REVIEWS
(2022)
Proceedings Paper
Engineering, Electrical & Electronic
A. Di Vito, A. Pecchia, M. Auf der Maur, A. Di Carlo
Summary: Recent photoluminescence studies on the tetragonal-to-orthorhombic phase transition of MAPbI(3) revealed residual tetragonal phase existing far below the transition temperature, with spectral signatures from quantum confined tetragonal domains. A theoretical model of coexisting tetragonal and orthorhombic MAPbI(3) was proposed, based on tight binding simulations and tight binding parameters derived from particle swarm optimization. The impact of tetragonal domain dimension on the optical properties of MAPbI(3) was discussed.
2021 INTERNATIONAL CONFERENCE ON NUMERICAL SIMULATION OF OPTOELECTRONIC DEVICES (NUSOD)
(2021)
Article
Chemistry, Multidisciplinary
Boyuan Zhang, Marc H. Garner, Liang Li, Luis M. Campos, Gemma C. Solomon, Latha Venkataraman
Summary: Designing highly insulating sub-nanometer molecules is challenging due to the exponential increase in tunneling conductance with decreasing molecular length and the difficulty of achieving full conductance suppression with destructive quantum interference. However, a series of small saturated heterocyclic alkanes have been found to exhibit conductance suppression through destructive interference, paving the way for the chemical design of short molecular insulators using organic molecules.
Article
Materials Science, Multidisciplinary
Daniele Barettin, Matthias Auf Der Maur, Alessandro Pecchia, Yan Zhang, Morten Willatzen, Zhong Lin Wang
Summary: By utilizing an 8-band k center dot p model, it has been shown that increasing the thickness of the InN quantum well in a GaN-InN-GaN device can change the bandgap properties of InN material and significantly tune the current-voltage characteristics. It is confirmed that piezoelectricity plays a crucial role in controlling electron transport through the InN layer.
JOURNAL OF PHYSICS-MATERIALS
(2021)
