Bulletin of the American Physical Society
2018 Annual Meeting of the APS Mid-Atlantic Section
Volume 63, Number 20
Friday–Sunday, November 9–11, 2018; College Park, Maryland
Session D03: Quantum Materials |
Hide Abstracts |
Chair: Nitin Samarth, Pennsylvania State University Room: Edward St. John 2208 |
Saturday, November 10, 2018 9:30AM - 10:06AM |
D03.00001: Giant nonlinear optical responses in polar Weyl semimetals Invited Speaker: Liang Wu The second-order optical nonlinearity σ (2) (ω) has been a focus of basic research and technological development for decades as it is both a probe of inversion symmetry breaking in media and the basis for generating coherent light from far-infrared to ultraviolet wavelengths. Here, we focus on the relation between band geometry and nonlinear optics. We measured second harmonic generation (SHG) with incident photon energy from 0.4 eV - 1.6 eV on a polar semimetal TaAs with a sharp resonant peak detected at 0.7 eV, that is larger than previously measured in any crystal. Our discovery of a giant anisotropic σ (2) (ω) in TaAs raises the following questions: what is special about TaAs and/or polar metals that accounts for large resonant optical nonlinearity, and, is there a fundamental upper bound on σ (2) (ω) in such inversion breaking crystals? I will describe in the Rice-Mele model based on the band-geometric theory of nonlinear optical response that addresses these questions. |
Saturday, November 10, 2018 10:06AM - 10:18AM |
D03.00002: Microstructural Engineering of the UV/Near-UV Photocurrent Production in VO2 Thin Film Based Detectors Jason Creeden, Scott E Madaras, Douglas Beringer, Melissa Beebe, Irina Novikova, R. Ale Lukaszew We sought to optimize the photosensitivity of VO2 thin films in the near-UV (NUV) and UV regions after recent reports demonstrating it is possible to push the typical IR photoresponse of VO2 into the visible spectrum via thin film growth on TiO2:Nb substrates. By controlling the microstructure of the films via deposition parameters and substrate doping, we optimize VO2 growth for TiO2 and TiO2:Nb substrates and compare their photocurrent response using 405 nm (NUV) and 254 nm (UV) light. We found that VO2 on TiO2:Nb heterostructure demonstrates greater photocurrent response. By measuring the external quantum efficiency (EQE), we found a dramatic photosensitivity improvement for the VO2 on TiO2:Nb compared to undoped TiO2 substrates. Notably, we demonstrated greater than 100% EQE for VO2 on TiO2:Nb for both wavelengths and an improvement in the EQE using UV in comparison to the NUV. Finally, we additionally propose a mechanism for this photoresponse which potentially allows for greater than 100% EQE. |
Saturday, November 10, 2018 10:18AM - 10:30AM |
D03.00003: Low-temperature and dynamic magnetism of frustrated 5d2 Li4MgOsO6 in comparison with 5d3 Li3Mg2OsO6 Jeremy P. Carlo, Shahab Derakhshan Geometric magnetic frustration (GMF) has attracted substantial interest due to the exotic physics and rich phase diagrams revealed by the cancellation of normally-dominant magnetic interactions, giving impetus for the search for novel frustrated systems, most often based on antiferromagnetic correlations between magnetic ions decorating triangular or tetrahedral lattices. We report low-temperature magnetic susceptibility and muon spin relaxation results on Li4MgOsO6 and Li3Mg2OsO6, members of the A5BO6 "rock salt ordered" family of frustrated materials. In Li3Mg2OsO6 we find spin freezing below 12K. In Li4MgOsO6, which can crystallize into either orthorhombic Fddd or monoclinic C2/m crystal symmetries depending on synthesis conditions, we find magnetism consistent with glassy-like behavior dominating below 2K, with partial ordering and evidence for dynamics at somewhat higher temperatures. |
Saturday, November 10, 2018 10:30AM - 11:06AM |
D03.00004: Correlated Nanoelectronics Invited Speaker: Jeremy Levy The study of strongly correlated electronic systems and the development of quantum transport in nanoelectronic devices have followed distinct, mostly non-overlapping paths. Electronic correlations of complex materials lead to emergent properties such as superconductivity, magnetism, and Mott insulator phases. Nanoelectronics generally starts with far simpler materials (e.g., carbon-based or semiconductors) and derives functionality from doping and spatial confinement to two or fewer spatial dimensions. In the last decade, these two fields have begun to overlap. The development of new growth techniques for complex oxides have enabled new families of heterostructures which can be electrostatically gated between insulating, ferromagnetic, conducting and superconducting phases. In my own research, we use a scanning probe to “write” and “erase” conducting nanostructures at the LaAlO3/SrTiO3 interface. The process is similar to that of an Etch-a-Sketch toy, but with a precision of two nanometers. A wide variety of nanoscale devices have already been demonstrated, including nanowires, nanoscale photodetectors, THz emitters and detectors, tunnel junctions, diodes, field-effect transistors, single-electron transistors, superconducting nanostructures and ballistic electron waveguides. These building blocks may form the basis for novel technologies, including a platform for complex-oxide-based quantum computation and quantum simulation. |
Saturday, November 10, 2018 11:06AM - 11:18AM |
D03.00005: Eigenmodes hybridization enables lattice induced transparency in terahertz metasurfaces. Riad Yahiaoui, Joshua A Burrow, Andrew Sarangan, Jay Mathews, Imad Agha, Thomas A Searles To induce a lattice dependent transparency, the design in the terahertz metasurface must possess an inherent Fano or EIT-like spectral feature, typically excited by asymmetry or superposition of geometric responses. Here we investigate the near neighboring coupling phenomenon in multi-gap split ring resonators (SRRs) exhibiting four fold symmetry. By increasing the distance between neighboring meta-atoms, we successfully demonstrate the realization of a lattice induced transparency (LIT) by coupling the first-order mode (i.e., fundamental dipole) and the second-order mode excited in the SRRs. The results we obtained indicate the potential use in different fields including sensing, slow light and optical delay lines. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700