Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session Z21: Carbon Nanostructures |
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Sponsoring Units: DCMP Chair: Subham Majumdar, Indian Assoc/Cultivation of Sc Room: Room 213 |
Friday, March 10, 2023 11:30AM - 11:42AM |
Z21.00001: Tunable Giant Ultraviolet Circular Dichroism in Wafer-Scale Carbon Nanotube Architectures with Engineered Chirality Jacques Doumani, Minhan Lou, Oliver Dewey, Nina Hong, Yohei Yomogida, Matteo Pasquali, Kazuhiro Yanagi, Riichiro Saito, Junichiro Kono, Weilu Gao Controlling the dissymmetric interaction of circularly polarized light with solid-state materials is required for chiral quantum photonic systems. The extraordinarily strong 1D quantum confinement of electrons and photons in carbon nanotubes (CNTs) leads to robust quantum phenomena, ideally suited for developing high-operating-temperature devices to generate, modulate, and detect quantum light. Although circular dichroism has been observed in enantiomer-enriched chiral CNT suspensions, there have been no reports on macroscopic assemblies of ordered CNTs with engineered chiroptical properties. Here, we demonstrate tunable, giant, and structure-induced deep-ultraviolet circular dichroism ellipticity in wafer-scale films of ordered racemic CNTs prepared using two approaches: mechanical-rotation-assisted vacuum filtration and 3D chiral stacking of aligned CNTs. We are able to engineer the chirality, including the strength and sign of circular dichroism, by adjusting the rotation forces and the twist angles, respectively, in the two approaches. These experimental observations fully agree with both transfer-matrix calculations and full-wave electromagnetic numerical simulations. |
Friday, March 10, 2023 11:42AM - 11:54AM |
Z21.00002: Phases of graphene monoxide: Two-dimensional crystal forms of solid carbon monoxide Danylo Radevych, Marija Gajdardziska-Josifovska, Michael Weinert Graphene monoxide (GmO) – a 2-dimensional crystal form of solid carbon monoxide – has been demonstrated as a promising candidate for the Li-ion battery anode material due to properties of its first discovered structure, named α-GmO. In this work, new phases of GmO are predicted with density functional theory computations, in addition to previously experimentally discovered and theoretically modeled α- and β-GmO phases. Structure parameters, electronic and mechanical properties of the reported phases are investigated and compared. It is suggested that all phases of GmO can co-exist due to small formation energy differences. Hence a synthesis process of the pure material containing only one phase of GmO can be experimentally challenging. The models belong to different space groups and have different band structures, with some being insulators, semiconductors, or conductors. From analysis of the elastic moduli, it is concluded that GmO structures are softer than graphene and are likely to change their lattice parameters if they are present in a nanocomposite with graphene. |
Friday, March 10, 2023 11:54AM - 12:06PM |
Z21.00003: Characterization of Ultra Clean Carbon Nanotubes for Surface Acoustic Wave Integration Jameson G Berg, Neda Lotfizadeh, Dublin Nichols, Mitchell J Senger, Wade De Gottardi, Ethan D Minot, Vikram V Deshpande Integrating surface acoustic waves (SAWs) with carbon nanotubes promises to be a robust platform to study the effects of periodic electric potentials on one-dimensional (1D) electron systems. Suspended single-walled carbon nanotubes (SWCNTs) are perfect examples of exact one-dimensional electron systems with rich transport phenomena ripe for integration with SAWs. In this work, we report on the characterization of ultra-high-quality of SWCNTs and preliminary SAW transducers for integrated experiments. The ultra-high quality of our SWCNTs has exposed subtle warping of graphene’s Dirac bands, leading to inequivalent K and K’ group velocities. In the Fabry-Perot regime, the asymmetric velocities form long-period conductance oscillations versus gate voltage attributed to Sagnac-like quantum interference [1,2]. We also see effects in the shell-filling quantum dot regime as spontaneous doubly degenerate energy levels are inserted periodically between the expected four-fold degenerate energy levels. This effect highlights the presence of a vernier energy scale between the allowed energy levels of a finite-sized ultraclean carbon nanotube [3]. The plethora of rich electronic phenomena present in SWCNT transport, along with the long CNT length and improvements in small SAW wavelength (down to ~200 nm), present a compelling platform to expand the complexities of 1D physics. |
Friday, March 10, 2023 12:06PM - 12:18PM |
Z21.00004: Point Contacts to Atomically Precise Graphene Nanoribbons Wenhao Huang, Oliver Braun, Jian Zhang, Michel Calame, Mickael Perrin Bottom-up synthesized graphene nanoribbons (GNRs) are an emerging class of designer quantum materials that possess superior properties including atomically controlled uniformity and chemically tunable electronic properties. GNR-based devices are promising candidates for next-generation electronic, spintronic, and thermoelectric applications. However, a significant portion of the GNRs synthesized to date are unstable under ambient conditions and require protection from the environment. Here, we encapsulate 9-atom wide armchair GNRs (9-AGNRs) in Hexagonal Boron Nitride (h−BN) and contact them using metallic side contacts, leading to a point contact at the GNR/metal interface. At 9 K, quantum dot (QD) behavior with well-defined Coulomb diamonds is observed, with additional energies in the range of 20 to 400 meV. For increasing temperature, charge transport through the GNR film, occurring via a combination of temperature-activated hopping and nuclear tunneling, starts to dominate, with a crossover between QD transport and film transport occurring at around 100 K. At room temperature, our short-channel field-effect transistor devices exhibit on/off ratios as high as 3×105. Overall, our work demonstrates that 9-AGNRs can be contacted while being encapsulated in h−BN. This enables a whole range of GNR candidates that are unstable under ambient conditions to be incorporated into electronic and spintronic devices. |
Friday, March 10, 2023 12:18PM - 12:30PM |
Z21.00005: Theory and spatially resolved vibrational spectroscopy of confined water in carbon nanotubes Xin Jin, Deliang Bao, Xintong Xu, Yu Wang, Arun Majumdar, Hachtel Jordan, Sokrates T Pantelides Water confined in carbon nanotubes (CNTs) has been a topic of significant experimental and theoretical interest for several decades. The nature of the confined water is still unclear. Atomic vibrations are the property directly correlated with molecular configurations and bonding. Here we report initial results of a comprehensive theory-experiments project on sample fabrication and characterization of water-filled CNTs, spatially-resolved scanning transmission electron microscopy (STEM) and monochromated (high energy resolution) electron energy loss spectroscopy (EELS) used to probe individual CNTS, and theoretical vibrational spectra based on density-functional-theory molecular-dynamics simulations. The EEL spectra show a peak at 460 meV with no corresponding peak at 420 meV (the O-H stretch mode of water at room temperature). Simulations have been performed for both single- and double-wall nanotubes, allowing full vibrational freedom for all carbon atoms. Comparison with results obtained with fixed-position carbon atoms enable detailed analysis of the origins of observed peaks and frequency shifts in terms of the bonding rearrangements caused by the CNT vibrations. The role of the effective confined-water density is elucidated via a novel way to characterize this density. |
Friday, March 10, 2023 12:30PM - 12:42PM |
Z21.00006: CNT coalescence within graphitic fibers through ultraviolet pulsed laser annealing Rachel Martin, Zachary Piontkowski, Mitchell Trafford, Wyatt Hodges, Anthony McDonald, Lyle Brunke, Matteo Pasquali, Michael P Siegal We studied ultra-rapid thermal annealing using a pulsed excimer laser to heat and promote coalescence of individual single-walled carbon nanotubes (CNTs) within fibers to improve transport properties. Individual CNTs consist of graphene cylinders with electrical (>10,000 MS/m) and thermal (>3,000 W/m•K) conductivities that are significantly higher than metals. CNT fibers consist of bundles of CNTs that are in poor physical contact, resulting in large decreases in conductivity between nanotubes. Recently, furnace annealing up to 1700°C demonstrated that the CNTs within these bundles coalesce to form larger diameter CNTs, however, this process is slow and has a high thermal budget. Instead, we demonstrate that pulsed-laser annealing (PLA) with 248 nm ultraviolet (UV) light can also achieve CNT coalescence within the fibers due to strong UV absorbance by opaque CNTs at a reduced thermal budget. Average CNT diameters within a fiber are determined using Raman spectroscopy, with changes to radial breathing modes specific to CNTs correlating to increases in diameter as a function of PLA conditions. We hypothesize that CNT coalescence within the fibers will decrease the local resistance between adjacent CNTs for electric and thermal transport, thus potentially improving both properties for the entire fiber. |
Friday, March 10, 2023 12:42PM - 12:54PM |
Z21.00007: Chemistry and Magnetism Meet at the Zigzag Edges of Graphene Michele Pizzochero, Efthimios Kaxiras Although the unconventional π-magnetism at the zigzag edges of graphene holds promise for a wide array of applications, whether and to what degree it plays a role in their chemistry remains poorly understood. Here, we investigate the addition of a hydrogen atom - the simplest yet the most experimentally relevant adsorbate - to zigzag graphene nanoribbons (ZGNRs). We show that the π-magnetism governs the chemistry of ZGNRs, giving rise to a site-dependent reactivity of the carbon atoms and driving the hydrogenation process to the nanoribbon edges. Conversely, the chemisorbed hydrogen atom governs the π-magnetism of ZGNRs, acting as a spin-1/2 paramagnetic center in the otherwise antiferromagnetic ground state and spin-polarizing the charge carriers at the band extrema. Our findings establish a comprehensive picture of the peculiar interplay between chemistry and magnetism that emerges at the zigzag edges of graphene. |
Friday, March 10, 2023 12:54PM - 1:06PM |
Z21.00008: Graphene oxide nanoplatelets: The role of hydroxyl and epoxy bridges in basic physical properties and global reactivity J. J. Prias-Barragan Basic physical properties and global reactivity in graphene oxide (GO) nanoplatelets, were studied experimentally by different physical characterization techniques, as presented here. GO structures with hydroxyl and epoxy bridges were proposed and the first principles calculations were performed, via density functional theory (DFT) in GO structures; obtaining, a high concordance between theory and experiments. These results suggest a basic description of the GO physics and potential technological applications of GO in advanced electronics of sensors and devices. |
Friday, March 10, 2023 1:06PM - 1:18PM |
Z21.00009: The Impact of Electric Fields’ Direction on Water Desalination Performance of a Nano-filter; A Molecular Dynamics Study Samaneh Rikhtehgaran In this study, molecular dynamics simulations are used to investigate the influence of a vertical and a horizontal electric field on the water desalination performance of a nono-filter. The nano-filter is made of a carbon nanotube and graphene layers. The concentration of the aqueous NaCl solution used in this study is close to a seawater salinity. This project aims to investigate the influence of the electric fields’ direction on ion separation and water desalination performance of a nano-filter. These results might help better control the water transport through the nano-filter and for the design of highly efficient water desalination filters. |
Friday, March 10, 2023 1:18PM - 1:30PM |
Z21.00010: Influence of temperature on electrical conductivity and bandgap energy in graphene oxide films Diego Sanchez, Jhon Prias Temperature influence on electrical and bandgap energy (Eg) in Graphene oxide films (GO)/baquelite, are presented here. GO films were synthesized by employing the double thermal decomposition (DTD) method. Compositional, vibrational, morphological, and electrical properties were studied. Results revealed that increased temperature (T), increases electrical conductivity and decreases Eg, like a semiconductor material. The main conduction mechanism was described by 3D-variable range hopping and the Eg(T) dependence was described employing the Varshni model. These results suggest that GO films are an attractive material for advanced electronic sensors and devices. |
Friday, March 10, 2023 1:30PM - 1:42PM |
Z21.00011: Strong photon-magnon coupling using a lithographically defined, low damping molecular ferrimagnet Qin Xu, Harry Cheung, Donley Cormode, Tharnier Puel, Huma Yusuf, Michael Chilcote, Michael E Flatté, Ezekiel W Johnston-Halperin, Gregory D Fuchs We report on strong coupling between microwave resonator photons and magnons hosted by the molecular ferrimagnet vanadium tetracyanoethylene V[TCNE]x. Our work is motivated by the challenge of scalably integrating an lithographically patterned, low-damping magnetic material with planar superconducting circuits, thus enabling a host of new quantum circuit designs that leverage the properties of magnetism to create new function. We take advantage of the properties of V[TCNE]x, which has ultra-low intrinsic damping, can be grown at low processing temperatures on arbitrary substrates, and patterned via electron beam lithography. We demonstrate the scalable, lithographically integrated fabrication of hybrid quantum magnonic devices consisting of a thin-film superconducting resonator coupled to low-damping, thin-film V[TCNE]x. Our devices exhibit a cooperativity as high as 1181 at T <!--[if gte msEquation 12]>~ 0.4 K, which is deep in the strong coupling regime and suitable for quantum circuit integration. Owing to the unique properties of V[TCNE]x, our samples reveal a spectrum of high-order magnon modes that couple to the resonator. This work paves the way for the flexible exploration of high-cooperativity hybrid magnonic quantum devices in which magnonic circuits may be scalably integrated with superconducting circuits. |
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