Bulletin of the American Physical Society
APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session Y09: Two-Dimensional Phases in Oxide Heterostructures |
Hide Abstracts |
Sponsoring Units: DMP Chair: Ankit Disa, Max Planck Inst Structure & Dynamics of Matter Room: LACC 301A |
Friday, March 9, 2018 11:15AM - 11:27AM |
Y09.00001: Abstract Withdrawn
|
Friday, March 9, 2018 11:27AM - 11:39AM |
Y09.00002: Shubnikov de Hass oscillation in Two-dimensional electron liquid at (111) oriented SrTiO3 interfaces Ziqiao Wang, Jing Wang, Liping Chen, Qi Li Two-dimensional electron liquid (2DEL) at SrTiO3 surfaces and interfaces have attracted much attention due to their fascinating exotic properties. Most of the studies reported so far have been conducted on the (001) orientation. We created two-dimensional electron liquids in SrTiO3 (111) orientation. Hall measurements reveal a high mobility up to 20000 cm^2/V*s and a carrier concentration of 3*10^14/cm^2. We were able to control the dimensionality based on the band engineering approach and systematically measured the Shubnikov de Hass oscillation (SdH) oscillations at different filling levels. The carrier density was controlled by a gating sequence when difference carrier concentration states can be created with no gate voltage on (no applied electric fields) during the measurements. We observed very pronounced resistance quantum oscillation at low temperatures and magnetic fields up to 9 T. We conducted fast Fourier Transformation (FFT) of the oscillations which revealed the information on the Fermi surface and the filling of the multiple bands. We will discuss the results on the comparison of the near 3D to 2D systems with different band filling levels. |
Friday, March 9, 2018 11:39AM - 11:51AM |
Y09.00003: Tuning the Rashba Effect with Electrical Gating of Ultra-thin LaTiO3/SrTiO3 Heterostructures Michael Veit, Remi Arras, Brad Ramshaw, Mun Chan, Rossitza Pentcheva, Yuri Suzuki Emergent metallic behavior at the interface of the Mott insulator LaTiO3 and the band insulator SrTiO3 has been explained in terms of charge redistribution at the interface combined with strain-induced electronic structure modification. We have studied ultra thin (3 unit cells) films of LaTiO3 and found evidence for a giant Rashba effect from quantum oscillations with an associated Berry phase, weak antilocalization in the magnetoresistance, and anisotropic in-plane magnetoresistance. In order to tune these properties, we have electrically back-gated these films. We have found a transition from a nonlinear to a linear Hall effect, a change in sign of the magnetoresistance, and, most interestingly, a peak in the zero field resistance. Based on density functional theory calculations, we attribute the nonlinear to linear Hall effect transition to an emptying of a dxz+yz band. The peak is attributed to tuning the Fermi energy across a Rashba effect induced Dirac point. |
Friday, March 9, 2018 11:51AM - 12:03PM |
Y09.00004: Growth of epitaxial SrVO3 and LaVO3 thin films Jason Hoffman, Alyson Spitzig, Jennifer Hoffman Perovskite vanadates have recently attracted significant attention for their wide-range of functional properties. Below around 140 K, LaVO3 is an orbitally ordered antiferromagnetic insulator, while SrVO3 is a strongly correlated paramagnetic metal. In this work, we use oxygen-plasma assisted molecular beam epitaxy (MBE) to deposit epitaxial LaVO3 and SrVO3 thin films on insulating SrTiO3 substrates. We use ex-situ x-ray diffraction and magnetotransport measurements to compare the properties of (001) and (111)-oriented samples. We also discuss the behavior of LaVO3 / SrVO3 heterostructures, where above-room-temperature ferromagnetism has been reported and ferroelectricity has been predicted. |
Friday, March 9, 2018 12:03PM - 12:15PM |
Y09.00005: High room-temperature electron mobility in hybrid MBE-grown La-doped SrSnO3 films Tianqi Wang, Abhinav Prakash, Laxman Thoutam, William Nunn, Turan Birol, Bharat Jalan Strain-engineered, phase-pure, epitaxial, and stoichiometric La-doped SrSnO3 films were grown using hybrid molecular beam epitaxy on LaAlO3 (001) and GdScO3 (110) substrates. High room-temperature electron mobility of 61 cm2V-1s-1 was achieved on GdScO3 at a carrier concentration of 7×1019 cm-3, with still room for improved with proper control over structure and doping. Through systematic study of temperature-dependent electronic and magneto-transport behavior, we will show that substrate-induced dislocations can have a strong influence on the electron phase coherence length resulting in a dimensionality crossover from 2D to 3D weak localization. We will then demonstrate that growth-induced cation non-stoichiometry results in a crossover from weak to strong localization of electronic carriers in La-doped SrSnO3 films on LaAlO3. Finally, we will discuss the correlations between electronic transport mechanisms and structural defects associated with cation non-stoichiometry and dislocations. |
Friday, March 9, 2018 12:15PM - 12:27PM |
Y09.00006: Experimental control of the structure in SrCuO2 ultrathin films Jiunn-Yuan Lin, P. C. Chiang, Y. H. Chu A two-dimensional (2D) CuO2 plane is the basis for studying high-Tc superconducting cuprate. The formation of the CuO2 plane in oxide thin films is limited by the strong electrostatic instability at the termination between the thin film and substrate. In this study, the ultrathin (1 - 20 uc) SrCuO2 films were successfully grown on TiO2-terminated SrTiO3 substrates using pulsed laser deposition. The thickness-dependent structural transformation of the SrCuO2 films was studied by polarized x-ray absorption spectroscopy (XAS) at the Cu L edge. XAS with theoretical calculations clearly distinguished chain-type structure and plane-type structure. XAS show that the out-of-plane spectral weight decreases as the number of layer increases. In the 7uc SrCuO2 ultrathin films, XAS shows the same behavior as that of the infinite-layer sample. |
Friday, March 9, 2018 12:27PM - 12:39PM |
Y09.00007: Programming spatial light modulations using mobile electrons Ming Yang, Weitao Dai, Hyungwoo Lee, Jungwoo Lee, Chang-Beom Eom, Cheng Cen The perturbations that can be generated by two-dimensional distributions of mobile electrons on visible light fields are usually very weak, which makes their visualizations difficult and also limits their optoelectronic applications. In this study, we demonstrate the reprogrammable spatial light modulations achieved by two-dimensional electron gas structures formed at complex oxide interfaces. This result is enabled by a field-induced polar phase transition at the interface and the related linear electro-optic effect. Using tailored light modulation configurations, nature of the phase transition was systematically studied by visible light imaging. Benefiting from this effect, the fast optical microscopy measurement produced quick visualizations of the interface carrier distributions and real-time monitoring of the surface charge depletion process triggered by the large local field. These results demonstrate the tantalizing possibility of generating designed light manipulations using mature carrier-controlling techniques developed for low dimensional electron systems. |
Friday, March 9, 2018 12:39PM - 12:51PM |
Y09.00008: Electrolyte Gating of Two-Dimensional Electron Gas at Oxide Interfaces Shengwei Zeng, Thirumalai Venkatesan, Ariando Ariando We demonstrate the modulation of electrical transport properties in both crystalline and amorphous LAO/STO interfaces by electric field effect using electric double layer transistor (EDLT) configuration. For the crystalline LAO/STO interfaces, reversible metallic-insulating phase transition and field-effect transistor operation are observed, which indicates that the carriers in the interfaces could be reversible accumulated and depleted. Moreover, enhancement of mobility and the resultant quantum oscillations of the conductance due to the depletion of carrier density are obtained. For the amorphous LAO/STO interfaces in which the conductivity is caused by oxygen vacancy formation, it is found that filling of oxygen vacancies and therefore, the decrease in carrier density after liquid gating, suggesting the presence of oxygen migration. The filling effect causes the reconstruction of interfacial band structures, that can be controlled by the LAO overlayer deposition temperature, suggesting a method for tuning the band structures and oxidation states of buried interfaces. |
Friday, March 9, 2018 12:51PM - 1:03PM |
Y09.00009: Magnetoresistance Anisotropy and Anomalous Hall Effect in Sr3Ru2O7 Patrick Marshall, Susanne Stemmer We report on the transport properties of hybrid molecular beam epitaxy-grown thin films of the bilayer perovskite Sr3Ru2O7. Consistent with prior observations, the films undergo a low-temperature metamagnetic transition as evidenced by maxima in the magnetoresistance at magnetic fields near 8 T and 5 T with the magnetic field applied out-of-plane and in-plane, respectively. A striking anisotropy in the magnetoresistance is observed with the magnetic field oriented in-plane. Positive magnetoresistance is observed at low fields when the current is transverse to the magnetic field, while the magnetoresistance is negative with the current parallel to the field. This anisotropy is accompanied by an anomalous signal in the Hall effect, which persists to temperatures as high as 150 K. These observations are suggestive of previously unreported phenomena arising from the interplay of the band structure and complex nature of the magnetism in Sr3Ru2O7. |
Friday, March 9, 2018 1:03PM - 1:15PM |
Y09.00010: Revealing the complex band structure of LAO/STO interface by high magnetic field quantum transport M. Yang, K. Han, Shengwei Zeng, Zhen Huang, M. Goiran, W. Escoffier, Ariando Ariando The transport properties of LAO/STO interface were investigated under high magnetic field. We observe oscillations of the magneto-resistance with altered periodicity when plotted versus inverse magnetic field. This effect can be linked to the Rashba spin-orbit coupling and remains consistent with large negative magneto-resistance when the field is parallel to the sample’s plane. The gate dependent data at very low temperature (down to 40 mK) show a richer Shubnikov de-Haas oscillations in the longitudinal magneto-resistance RXX(B) with several frequencies in the FFT (Fast Fourier Transform) spectrum. From the gate dependant results, we infer the presence of many sub-bands involved in the quantum transport properties, yielding a complex Landau Level diagram. |
Friday, March 9, 2018 1:15PM - 1:27PM |
Y09.00011: Field Effect in Top-gated Devices Based on NdTiO3/SrTiO3 Heterointerfaces Xinxin Cai, Yilikal Ayino, Peng Xu, Jin Yue, Laxman Raju Thoutam, Bharat Jalan, Vlad Pribiag The interface between a Mott insulator, RTiO3 (where R is a rare-earth element), and SrTiO3 hosts an ultra-high density two-dimension electron gas, which can display a broad range of correlated electron phenomena, ranging from magnetism to superconductivity. Due to the dielectric constant of SrTiO3, up to ~30,000 at low temperatures, the use of SrTiO3 as a top-gate dielectric is expected to provide new opportunities for locally tuning the very large electron densities which are present in complex oxide interface devices. We discuss the fabrication and electrical measurements of top-gated Hall bars based on hybrid MBE-grown NdTiO3/SrTiO3 heterostructures. |
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