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 W34: Transport Properties in 2D Materials and Semiconductors |
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Sponsoring Units: FIAP Chair: Akihiro Ino, Kurume Institute of Technology Room: Room 226/227 |
Thursday, March 9, 2023 3:00PM - 3:12PM |
W34.00001: Finite-temperature Raman spectroscopy of BaZrS3 explained by first principles theory Florian Knoop, Matan Menahem, Nimrod Benshalom, Jayakanth Ravichandran, Rafael Jaramillo, Olle Hellman, Omer Yaffe We combine ab initio simulations and Raman scattering measurements to investigate BaZrS3, a highly polarizable yet lead-free chalcogenide Perovskite with strong optical response [1]. In particular, we focus on the temperature evolution of first- and second-order polarization-oriented (PO) and unpolarized Raman scattering. We present how anharmonic phonon theory coupled to ab initio simulations [2] can shed light on the underlying microscopic processes both quantitatively and qualitatively. We discuss the methodological challenges related to modeling similarly complex low-symmetry compounds at finite temperature such as correct treatment of long-range electrostatic interactions producing, e.g., LO/TO splitting. We conclude by giving remarks on other dielectric properties, e.g., infrared absorption, that can be obtained in the same framework in a numerically efficient way. |
Thursday, March 9, 2023 3:12PM - 3:24PM |
W34.00002: Fluctuation contributions to quantum oscillations in excitonic insulators Andrew A Allocca, Nigel R Cooper The measurement of the de Haas-van Alphen effect in insulating systems kicked off a flurry of theoretical work to explain how quantum oscillation phenomenon, once thought intrinsic to metals, can manifest in gapped systems. For insulating systems with rigid gaps or interaction-generated gaps described by mean field theory, quantum oscillations are found to be exponentially suppressed for weak magnetic fields by a "Dingle damping" factor arising from the presence of the gap itself. Here we consider how collective fluctuations beyond the mean field description of these systems contribute to quantum oscillations. In a model excitonic insulator we examine the phase and amplitude (i.e. Higgs) fluctuations of the gap and find that they provide the dominant contributions to the oscillatory part of the free energy in this model for certain parameter regimes, and thus dominate quantum oscillations of the magnetization. |
Thursday, March 9, 2023 3:24PM - 3:36PM |
W34.00003: Diagonal and off-diagonal thermal conduction with resonant phonon scattering in Ni3TeO6 Heejun Yang, Xianghan Xu, Jun Han Lee, Yoon Seok Oh, Sang-Wook Cheong, Je-Geun Park The coupling between phonon and magnon is ubiquitous in magnetic materials and plays a crucial role in many aspects of magnetic properties, most notably in spintronics. Yet, this academically and technologically interesting problem still poses a severe challenge to a general understanding of the issue in certain materials. We report that Ni3TeO6 exhibits clear evidence of significant magnon-phonon coupling in both longitudinal thermal conductivity (κxx) and thermal Hall coefficient (κxy). The Debye-Callaway model, a phenomenological description for phonon heat conduction, can explain the measured magnetic field dependence of κxx(H) : phonon scattering from spin fluctuation in the paramagnetic phase and additional scattering due to magnon-phonon coupling in the collinear antiferromagnetic phase. We further suggest that a similar approach could be applied to understand the finite κxy values in Ni3TeO6. |
Thursday, March 9, 2023 3:36PM - 3:48PM |
W34.00004: Non-reciprocity in drag between quasi-1D quantum wires Dominique Laroche, Rebika Makaju, Harith Kassar, Sadhvikas Addamane We report 1D drag measurements in laterally coupled single layer GaAs/AlGaAs quantum wires. The drag resistance RD exhibits the standard modulation as the wires’ subband occupancy is varied, and the temperature dependence of the drag signal is non-monotonic. In contrast to previous Coulomb drag studies in one-dimensional GaAs systems, the drag signal is found to break Onsager relations, resulting in a symmetric and asymmetric drag signal. The anti-symmetric results are compared with theories for momentum transfer-induced drag while the symmetric contribution is interpreted in terms of a rectification of energy fluctuations. These results highlight the interplay between rectification and Luttinger liquid physics in mesoscopic quasi-1D quantum wires. |
Thursday, March 9, 2023 3:48PM - 4:00PM |
W34.00005: First principles study on oxygen deficiency induced new stable low-temperature rhombohedral HfO2-x Young-Joon Song, Nico Kaiser, Tobias Vogel, Eszter Piros, Taewook Kim, Philipp Schreyer, Stefan Petzold, Lambert Alff, Roser Valenti Hafnium dioxide (HfO2) has been extensively studied due to its promising properties, such as a high dielectric constant, wide band gap, and good thermodynamic stability. A number of polymorphs of HfO2 such as monoclinic, cubic, tetragonal, and orthorhombic were experimentally observed depending on temperature and pressure. Interestingly, a recent report showed the cubic phase of HfO2, normally crystalized above 2600 K, can be realized at low temperatures with a tiny rhombohedral distortion by adopting oxygen deficiency. [1] Here we address this new rhombohedral HfO2-x phase by means of density functional theory-based ab initio calculations which concur with the observations. Our calculations reveal that oxygen deficiency can lead to a stable rhombohedral HfO2-x phase; in addition, our analysis explains observed electronic properties in rhombohedral HfO2-x. Details in DFT as well as observations will be discussed. |
Thursday, March 9, 2023 4:00PM - 4:12PM |
W34.00006: Towards water desalination membrane and Terahertz bolometric detection using low dimensional material with defects. Abdelouahad El Fatimy, Ismail Benabdallah, Abderrahman Aberda, Petr Neugebauer, oleh Martyniuk, abdelmajid AitAbdelkader, brice D. Tchoffo Understanding and controlling defects in low-dimensional materials is essential to exploit these novel materials' potential for applications. We find that the device fabrication process substantially affects the defect density and that a higher defect density greatly enhances the bolometer device's performance, yielding faster response time and lower thermal conductance in a wide range of power and temperature [1]. We studied this defect using plasma sputtering and experimental and calculated Raman spectra. We show that we can determine the type of defects, which can help engineer a 2D membrane for water desalination and Terahertz Applications [2-3]. |
Thursday, March 9, 2023 4:12PM - 4:24PM |
W34.00007: Exploiting Functional Defects in Epitaxial Oxide Thin Films for Giant Piezoelectricity and Synaptic Electronics Huajun Liu Transition metal oxide thin films exhibit many interesting properties, including ferroelectricity, piezoelectricity and electrochemical activities for energy applications. Defects, such as oxygen vacancies, have long been known to be detrimental to certain functional properties of oxide thin films. However, by properly designing and controlled synthesis, the defects can be beneficial and even greatly improve the functional properties. |
Thursday, March 9, 2023 4:24PM - 4:36PM |
W34.00008: Formation of Erbium Doped Lithium Niobate Single Crystal in Glass via Femtosecond Laser Irradiation Collin Barker, Keith Veenhuizen, Volkmar G Dierolf, Himanshu Jain The formation of single crystals via femtosecond laser in 3D allows for the fabrication of more complex photonic packages and a higher number of optical elements in a single glass substrate. We have previously found a particular glass composition and growth parameters of laser power, scanning rate, and sample temperature that yield single crystal lithium niobate. A characteristic property of these laser written crystals is lattice rotation, a phenomenon of organized defects induced by stresses during the growth process. The challenges in finding sets of parameters yielding single crystal formation and in characterization are discussed, and their effect on the spectral properties of an erbium dopant is explored as various growth parameters are tuned. Engineering the spectral properties of doped laser written crystals has impacts on the fabrication of waveguide lasers and quantum memory applications. |
Thursday, March 9, 2023 4:36PM - 4:48PM |
W34.00009: Superior transport and optical properties of titanium oxynitride thin films: Liquid nitrogen assisted condensation of unwanted residual oxygen during film deposition Abiodun Odusanya, Dhananjay Kumar, Madison Jordan, Mark A Pfeifer This work reports our findings on how to mitigate an unwanted oxygenation process during the deposition of titanium oxynitride films (Ti-N-O) by a pulsed laser deposition method. The oxygenation is unavoidably caused by the residual oxygen in the chamber and/or oxygen impurity in the ambient gas used during the film deposition. The unwanted oxygenation process is controlled by means of an in-situ condensation process of residual/impurity oxygen on a metal trap held at liquid nitrogen temperature and placed near the film deposition stage. The oxygenation mitigation process results in achieving desired transport and optical properties in the Ti-N-O thin films. The optical properties of Ti-N-O films were found to be governed by intraband mechanism for N/O ratio (xx) in the film and by free electrons mechanism for N/O ratio (xx). The Ti-N-O films were found to possess both direct and indirect band gaps. The bandgap was found to reduce from 2.64 eV – 1.70 eV for direct and 1.70 eV – 0.36 eV for indirect. The presence of both direct and indirect bandgap is thought to be caused by the presence of strain in the material, which reduce the band gap and stimulated direct-to-indirect band gap transition. According to our x-ray diffraction measurements and analysis, a reduction in intensity and a shift of both (111) and (222) TiNO peaks to higher angles is observed as nitrogen pressure was increased. A counter-relationship of Bragg’s peak breadth was observed with the (111) and (222) peaks; the breadth of the (111) peak reduced while that of (222) increased with increasing nitrogen pressure. We have also observed higher lattice constant, crystallinity, and microstrain in the TiNO thin film samples deposited in the presence of liquid nitrogen trap with respect TiNO films deposited without liquid nitrogen trap. |
Thursday, March 9, 2023 4:48PM - 5:00PM |
W34.00010: Electric, dielectric and electrochemical measurements of Co:Mn-BTC bimetallic MOFs Manjeet Godara, Silvia Chowdhury, Nagy L Torad, Ahmed A El-Amir, Aditya Ashok, Ping Cheng, Ruijing Xin, Motasim Billah, Watcharop Chaikittisilp, Yusuke Yamauchi, Yusuf V Kaneti1, Nirat Ray Bimetallic metal-organic frameworks (MOFs) with two different metal ions in the inorganic nodes, show a synergistic effect and enhanced properties compared to their monometallic counterparts and have shown potential for applications in catalysis and electrochemical energy storage and conversion. In this work, we study the a.c. conductivity, dielectric properties, and electrochemical properties of Co and Mn-based MOFs. The AC conductivity and dielectric measurements are used to study the nature of charge transport in the system. We find that the conduction mechanism is frequency and concentration dependent, with the low-frequency contribution being dominated by a hopping mechanism and lattice response dominating at higher frequencies. We study the electrochemical responses and find a promising low overpotential of about 350 mV for Oxygen evolution reaction, within the system. |
Thursday, March 9, 2023 5:00PM - 5:12PM |
W34.00011: Extremely scaled hetero-junction channel TFT for advanced electronics SONU DEVI, Manohar Lal, Umesh Chand, Wang Xinghua, Chen Chun-Kuei, Evgeny Zamburg, Tsai Shih-Hao, Aaron Thean In this work, we demonstrate high performance short channel transistor using ultra-thin dual channel layer. The performance of the channel is comparable to emerging two-dimensional materials and superior to that of existing metal oxides. The active channel consists of amorphous Tin-doped Indium oxide and indium-gallium-zinc-oxide (ITO/IGZO) layers. We used sputtering to create the channel layer of combined thickness ~ 4 nm, and Atomic Layer Deposition to deposit high-quality hafnium oxide dielectric at low-temperature (<350°C), making our fabrication approach compatible with low-thermal budget Cu interconnects for back-end-of-line. Our approach results in significant improvement in TFT performance above our earlier published record results for 30 nm IGZO and 10 nm HfO2. In this study, we have achieved a highest field-effect mobility of 108 cm2V-1s-1 for ultra-thin ITO/IGZO channel with thickness of 4 nm. The introduction of a thin-layer ITO significantly suppresses the hysteresis in the device due to compensation of the interfacial/bulk traps. Short channel immunity is observed with significantly low off-state current <1 pA/µm, low subthreshold swing (SS) of <90 mV/decade and high ON/OFF ratio >108, for 50 nm channel length devices. Moreover, unlike Si, there is no significant degradation in long channel transistor performance as the active layer thickness changes from 33 nm to 4 nm. This is achieved by high carrier concentration in thin ITO and controlled electron flow through IGZO. |
Thursday, March 9, 2023 5:12PM - 5:24PM |
W34.00012: Electrolyte gated synaptic transistor based on an ultra-thin film of La0.7Sr0.3MnO3 miguel romera, alejandro lopez, Javier Tornos, andrea peralta, isabel barbero, gabriel Sanchez-Santolino, Maria Varela, Alberto Rivera, Carlos Leon, Jacobo Santamaria Developing electronic devices able to reproduce efficiently synaptic functionality is essential towards implementing fast and low energy consuming neuromorphic computing systems. Hybrid ionic/electronic three-terminal synaptic transistors are promising as artificial synapses since they can process information and learn simultaneously. In this work, we report on an electrolyte gated synaptic transistor based on an ultra-thin epitaxial film of La0.7Sr0.3MnO3 which is close to a metal-insulator transition. The dynamic control of oxygen composition of the manganite ultra-thin film with voltage pulses applied through the gate terminal allows reversibly modulating its electronic properties in a non-volatile manner. The conductance modulation can be finely tuned with the amplitude, duration and number of gating pulses, providing different alternatives to gradually update the synaptic weights. The transistor implements essential synaptic features such as excitatory postsynaptic potential, paired-pulse facilitation, long-term potentiation/depression of synaptic weights and spike-time-dependent plasticity (STDP). These results constitute an important step for the development of neuromorphic computing devices based on correlated manganites and open new paths towards enhancing the functionalities of synaptic transistors by using a half metallic ferromagnet as the transistor channel. |
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