Bulletin of the American Physical Society
APS March Meeting 2021
Volume 66, Number 1
Monday–Friday, March 15–19, 2021; Virtual; Time Zone: Central Daylight Time, USA
Session B42: Applications of 2D SystemsLive
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Sponsoring Units: DCMP Chair: Enrique Cobas, United States Naval Research Laboratory |
Monday, March 15, 2021 11:30AM - 11:42AM Live |
B42.00001: Electronic transport properties of low dimensional materials for ultrasensitive chemical sensors Maryam Abarashi, Mauro S. Ferreira, Claudia Gomes da Rocha Nanoscale sensors are widely used in industrial, environmental, and healthcare applications. The performance of chemical sensors depends on the host materials properties; low dimensional materials, e.g. graphene or carbon nanotubes, can be used as host materials to detect chemicals in the environment. These materials provide wide surface area per unit of volume capable of hosting concentrations of impurities, and they exhibit conductivity that is sensitive to chemical perturbations. In this work, we obtain the electronic transport properties of low dimensional materials to improve sensitivity and selectivity features of nanoscale chemical sensors. Volatile organic compounds, in the vicinity of the host, can cause alterations in their electronic properties. These alterations, such as variances in the energy-dependent conductance, can be investigated and categorized for each chemical component. We aim at solving the inverse-problem in which the hitherto unknown chemical impurities and their concentrations are determined by analyzing the conductance variance they impart onto the host. Our goal is to quantify the conductance fingerprint that some organic compounds induce on the host and to propose ways of improving the device sensitivity based on these findings. |
Monday, March 15, 2021 11:42AM - 11:54AM Live |
B42.00002: Characteristic Features of 1/f Noise in Graphene Field-Effect Transistor Photodetectors Zachary Henschel, Yifei Wang, Ho Xuan Vinh, Prashant Pradhan, Michael Cooney, Vinh Q Nguyen Graphene has been investigated intensely for optoelectronic applications, especially for field-effect transistor photodetectors. To evaluate the capability of weak light detection of a photodetector, the noise equivalent power can be estimated by characterizing the 1/f noise or flicker noise. Here, we experimentally demonstrate characteristic features of field-effect transistor photodetectors, which consist of a single graphene layer and a Ta2O5 dielectric thin film engineered by Atomic Layer Deposition method. The graphene field-effect mobility and low frequency 1/f noise are investigated in this study. Our devices show a low level of 1/f noise, with the spectral noise density of ~10-20 A2Hz-1 at 10 Hz, and a high carrier mobility of 6500 cm2/(V.s). The demonstrated graphene photodetector based on the field-effect transistor structure is important for the optoelectronic applications of graphene. |
Monday, March 15, 2021 11:54AM - 12:06PM Live |
B42.00003: Designing Interconnects Based on Graphene Nanoribbon Junctions Kristians Cernevics, Oleg Yazyev Graphene nanoribbons (GNRs) have emerged as potential building blocks for next-generation electronic devices, including the realization of all-graphene nanoscale electrical circuits. Junctions connecting two or more GNRs are hence inevitable in the interconnects of such circuits. We systematically address the electronic transport properties of 60° and 120° angled junctions connecting a pair of GNR leads of identical width and chirality that can be produced by means of the bottom-up synthesis. By using the tight-binding model calculations, we perform an exhaustive exploration of over 400,000 distinct configurations of GNR junctions, which allows us to formulate general guidelines into engineering the transport properties of GNR circuits and identify a large number of junctions that have conductance close to the limit defined by the ballistic conductance of ideal GNR leads. For instance, we find that sublattice imbalance in 120° junctions can support perfect transmission via a resonant state occurring at zero energy, hence yielding an ideal interconnect. To further streamline the process of engineering GNR junctions we also designed an intuitive online application for modeling and calculation of their electronic transport properties. |
Monday, March 15, 2021 12:06PM - 12:18PM Live |
B42.00004: Plasmonically enhanced mid-IR light source based on tunable spectrally and directionally selective thermal emission from nanopatterned graphene Muhammad Waqas Shabbir, Michael N Leuenberger We present a proof of concept for a spectrally selective thermal mid-IR source based on nanopatterned graphene (NPG). We solve the electrostatic problem of a conducting hyperboloid with an elliptical wormhole in presence of an in-plane electric field. The localized surface plasmons on the NPG sheet allow for the control and tuning of the thermal emission spectrum in the wavelength regime from 3µm to 12μm by adjusting the radius and period of holes in a hexagonal lattice structure. Our COMSOL calculations show an emission power of 11000 W/m2 at 2000K for a bias voltage of 23V by controlling the temperature of the hot electrons through the Joule heating. By generalizing Planck’s theory to grey body and deriving the nonlocal fluctuation-dissipation theorem with nonlocal response of surface plasmons, we show that the coherence length of the graphene plasmons and the thermally emitted photons can be as large as 13µm and 150µm, respectively, providing the opportunity to create a phased arrays of nanoantennas represented by the holes in NPG. Using FDTD calculations, CMT, and RPA, we develop the model of a mid-IR light source, which will pave the way to graphene-based optical mid-IR communication, mid-IR color displays, and mid-IR spectroscopy. |
Monday, March 15, 2021 12:18PM - 12:30PM Live |
B42.00005: Ultrasensitive mid-IR photodetector based on hybrid graphene and phase-changing vanadium oxide heterostructure operating above room temperature Muhammad Waqas Shabbir, Michael Leuenberger We present the model of an ultrasensitive mid-infrared (mid-IR) photodetector consisting of a hybrid heterostructure made of nanopatterned graphene (NPG) and vanadium dioxide (VO2) which exhibits a large responsivity of exceeding R=104 eV, a detectivity exceeding 1010, and a sensitivity in terms of noise-equivalent power (NEP) lower than 100 fW/sqrt(Hz) above room temperature by taking advantage of the phase change of a 3 nm thin VO2 sheet. Our proposed photodetector can reach an absorption in the graphene sheet of nearly 100% due to localized surface plasmons (LSPs) around the patterned circular holes. The geometry of the nanopattern and an electrostatic gate potential can be used to tune the wavelength peak in the mid-IR regime between 3 and 12 microns. After the photon absorption by the NPG sheet and the resulting phase change of VO2 the applied bias voltage Vb triggers a current through the VO2 sheet, which can be detected electronically on a sub-ms timescale, much shorter than the detection time of typical VO2 bolometers. Our proposed mid-IR photodetector reaches detectivities of cryogenically cooled HgCdTe photodetectors and sensitivities close to and field of view similar to VO2 bolometers while operating above room temperature. |
Monday, March 15, 2021 12:30PM - 12:42PM Live |
B42.00006: Observation of Aharonov-Bohm interference in graphene Fabry-Pérot quantum Hall interferometers Thomas Werkmeister, Yuval Ronen, Danial Haei Najafabadi, Andrew Pierce, James Ehrets, Alexander A Zibrov, Kenji Watanabe, Takashi Taniguchi, Amir Yacoby, Philip Kim The fractional quantum Hall effect has become the quintessential platform for investigating the properties of emergent anyons – quasiparticles which are neither fermions nor bosons. Signatures of the exchange statistics of these quasiparticles are beginning to be accessible in quantum Hall interferometers based on GaAs heterojunctions. However, the Fabry-Pérot interferometer, which is typically employed, suffers from competing charging effects that obscure the Aharonov-Bohm effect interference and signatures of anyons. Here, we use hBN-encapsulated monolayer graphene with top and bottom graphite gates to electrostatically define tunable Fabry-Pérot interferometers. Screening in the van der Waals heterostructure suppresses charging effects, yielding highly visible Aharonov-Bohm interference of integer quantum Hall edges. From this interference, we extract characteristic coherence lengths and edge mode velocities of various edges, which further demonstrate the advantages that graphene offers, and we compare gate-defined and etch-defined edge mode coherence. We will discuss progress towards interference of fractional quantum Hall modes in this system. |
Monday, March 15, 2021 12:42PM - 12:54PM Live |
B42.00007: Modeling of Graphene-Semiconductor Heterostructure Photodetectors Leslie Howe, Ho Xuan Vinh, Yifei Wang, Vinh Q Nguyen, Michael Cooney Graphene-based field-effect transistors are a promising technology for high-sensitivity photo-detection. However, the performance of graphene photodetectors is limited by the low photon absorption and the ultrafast carrier lifetime. To overcome these issues, the use of hybrid graphene-semiconductor structures has been employed. The defining features of these structures are a semiconductor thin film, used for photon absorption, and graphene which is utilized for the charge transport channel due to its ultrafast carrier mobility. With the interest in the development of these devices, it is important to understand how the absorber layer and graphene layer interact with incident light to create a strong photo-response. A model of the photoconductive mechanism is proposed showing that the photo-response for the devices is the modulation of the conducting surface due to the changing of the surface depletion layer. As shown by this simulation, several factors, including the doping concentration of the absorbing material, thickness of the absorbing material, and the size of the photodetectors have a strong impact on the performance of the graphene photodetectors. |
Monday, March 15, 2021 12:54PM - 1:06PM Live |
B42.00008: Gate-tunable Quantum Interferences in Monolayer Graphene PN Junctions Xi Zhang, Kan-Ting Tsai, Yujie Luo, Ke Wang Ballistic Dirac Fermions transport across gate-defined PN junctions exhibits strong dependence on incident angle due to the linear dispersion relationship. Multiple experiments have been performed utilizing the angle-dependence of Klein tunneling, in which novel electron-optics concepts including electron collimation [1] and Veselago lensing [2][3] have been demonstrated. Here we demonstrate preliminary experimental observations of quantum interferences based on these concepts. Preliminary transport data across carefully-engineered PN junctions will be presented and quantitative analysis based on Klein-tunneling probability will also be discussed. |
Monday, March 15, 2021 1:06PM - 1:18PM Live |
B42.00009: Transfer Matrix Approach For Plasmon Scattering In Closely Packed 1D Graphene Structures Viacheslav Semenenko, Mengkun Liu, Vasili Perebeinos We present a comprehensive study of graphene plasmon eigenmodes in 1D periodic structures formed by plasmonic junctions of different types [1]. Transmission and reflection coefficients composing a junction's scattering matrix are obtained directly from numerical solutions of equations describing the plasmons in the considered structures. The single junctions' obtained results are in perfect agreement with analytical formulas for the cases when they are available. Using our method as a reference, we analyze the limitations of the semi-phenomenological transfer matrix approach applied to the calculation of reflection from the double-junction structures. Our results can be useful in designing and calculating graphene plasmon resonators, waveguides, and switches. |
Monday, March 15, 2021 1:18PM - 1:30PM On Demand |
B42.00010: Nanometric Cavities for Mid-infrared Light Using Graphene Plasmons Itai Epstein, Frank Koppens Detecting small molecular signatures in the Mid-infrared and THz spectra requires a sufficient field intensity, especially in the case of few molecules. Graphene plasmons (GPs) are capable of confining MIR\THz light to very small dimensions [1], which become even smaller if a metallic surface is near the graphene, screening the GPs and enabling their compression up to 300 times their free-space wavelength [2].This large confinement, however, is also the reason why GP excitation is challenging and has been limited to micron-scale structures, hindering their actual confinement potential. |
Monday, March 15, 2021 1:30PM - 1:42PM On Demand |
B42.00011: Atomically precise, custom-design origami graphene nanostructures Hui Chen, Xianli Zhang, Yu-Yang Zhang, Dongfei Wang, Deliang Bao, Shixuan Du, Min Ouyang, Sokrates T Pantelides, Hongjun Gao The construction of atomically precise carbon nanostructures holds promise for developing materials for scientific study and nanotechnology applications. Recently, origami, the ancient art of paper folding, has been widely used in diverse areas, from architecture to battery design and DNA nanofabrication. However, atomically precise and controllable graphene origami for the creation of custom-design GNSs with quantum features remains an open challenge. In this talk, we will report that graphene origami is an efficient way to convert graphene into atomically precise, complex nanostructures. By scanning tunneling microscope manipulation at low temperature, we repeatedly fold and unfold graphene nanoislands (GNIs) along an arbitrarily chosen direction. A bilayer graphene stack featuring a tunable twist angle and a tubular edge connection between the layers is formed. Folding single-crystal GNIs creates tubular edges with specified chirality and one-dimensional electronic features similar to those of carbon nanotubes, whereas folding bicrystal GNIs creates well-defined intramolecular junctions. The present atomically precise graphene origami provides a platform for constructing carbon nanostructures with engineered quantum properties and, ultimately, quantum machines. |
Monday, March 15, 2021 1:42PM - 1:54PM On Demand |
B42.00012: Bilayer Photonic Graphene Mourad Oudich, Guangxu Su, Yuanchen Deng, Wladimir Benalcazar, Nikhil JRK Gerard, Minghui Lu, Peng Zhan, Yun Jing Drawing inspiration from the twisted bilayer graphene (TBG), we introduce a photonic bilayer analog consisting of two stacked graphene-like photonic crystals (PC) that support spoof surface plasmons. Beyond the twisting degree of freedom, the associated photonic dispersion can be controlled via the interlayer coupling strength that is readily tunable by varying the air-gap size between the two PCs. We numerically and experimentally characterize the band structures of AA and AB-stacked bilayer PC (BPC), as well as for the cases of sublattice exchanges (SE) with even and odd symmetries. Furthermore, we numerically predict the existence of magic angles in BPC, which are associated with ultra-flat bands resulted from interlayer hybridization. Finally, we uncover the topological corner mode within the topological band-gap associated with the SE even BPC. The proposed BPC could constitute a useful platform for identifying new quantum materials and stimulating the development of next-generation photonic devices with new degrees of freedom. |
Monday, March 15, 2021 1:54PM - 2:06PM On Demand |
B42.00013: Quantized resistance behavior in graphene Corbino p-n junction devices Albert Rigosi, Chieh-I Liu, Dominick Scaletta, Heather M. Hill, Antonio L Levy, Dinesh Patel, Mattias Kruskopf Just a few of the promising applications of graphene Corbino pnJ devices include two-dimensional Dirac fermion microscopes, custom programmable quantized resistors, and mesoscopic valley filters. In some cases, device scalability is crucial, as seen in fields like resistance metrology, where graphene devices are required to accommodate currents of the order 100 μA to be compatible with existing infrastructure. However, fabrication of these devices still poses many difficulties. Here we report quantized resistances in epitaxial graphene Corbino p-n junction devices held at the v=2 plateau (about 12.9 kΩ) that agree with numerical simulations performed with the LTspice circuit simulator. The formulae describing experimental and simulated data are empirically derived for generalized placement of up to three current terminals and accurately reflects observed partial edge channel cancellation. These results support the use of ultraviolet lithography as a way to scale up graphene-based devices with suitably narrow junctions that could be applied in a variety of subfields. |
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