Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session L06: Strong Electronic Correlations in Lanthanides and ActinidesFocus
|
Hide Abstracts |
Sponsoring Units: DCMP Chair: Krzysztof Gofryk, Idaho National Laboratory Room: BCEC 109A |
Wednesday, March 6, 2019 11:15AM - 11:27AM |
L06.00001: Exploring electronic anisotropy with strain in CeRhIn5 Sean Thomas, Adam P Dioguardi, Joe D Thompson, Priscila Rosa, Eric Bauer, Filip Ronning Strongly correlated material CeRhIn5 hosts a helical antiferromagnetic ground state at zero applied field. When a magnetic field of ~30 T is applied slightly away from the c-axis, a new phase emerges within the antiferromagnetic state with an XY electronic nematic character [1]. Here, we use a combination of uniaxial and biaxial strain devices to investigate the nematic susceptibility of CeRhIn5. A similar approach has been extensively used to investigate the nematic order in iron-based superconductors [2]. We will discuss signatures of the nematic susceptibility in the low-field region of the H-T phase diagram. |
Wednesday, March 6, 2019 11:27AM - 11:39AM |
L06.00002: Spin density wave and possible Fulde-Ferrell-Larkin-Ovchinnikov states in CeCoIn5 Duk Young Kim, Shizeng Lin, Eric Bauer, Filip Ronning, Roman Movshovich We examine interplay between spin density wave (SDW) and the putative Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in CeCoIn5. We use thermal conductivity measurement along a-axis in magnetic field applied at various angles away from the c-axis within the bc plane of this tetragonal compound. We compare our results to those of our theoretical model which shows that SDW state in CeCoIn5 is stabilized when the field is directed close to the ab plane. The SDW phase disappears when the field is rotated away from the ab plane.When the field is rotated toward the c axis, the FFLO state emerges while the SDW phase disappears. As a function of field, we observed the reduction of thermal conductivity for field close to the ab plane and the enhancement of thermal conductivity when field is close to the c axis, consistent with the theoretical expectations of additional contribution to the heat transpot from the FFLO nodal planes. |
Wednesday, March 6, 2019 11:39AM - 11:51AM |
L06.00003: Fermi surface evolution and crystal-field excitations in heavy-fermion compounds probed by time-domain terahertz spectroscopy Shovon Pal, Christoph Wetli, Farzaneh Zamani, Oliver Stockert, Hilbert v. Löhneysen, Manfred Fiebig, Johann Kroha In heavy-fermion (HF) compounds, the existence of heavy quasiparticles (QPs) is signaled by an enlarged Fermi volume. The energy scale for heavy QP formation is believed to be the Kondo lattice temperature. Hence, the origin of a large Fermi volume observed at temperatures much higher than the Kondo lattice temperature has recently been a controversial issue. We measure the quasiparticle weight in the HF compound CeCu6-xAux (x=0, 0.1) by time-resolved THz spectroscopy for temperatures from 2 K up to 300 K. This method distinguishes contributions from the heavy Kondo band and from the crystal-electric-field satellite bands by different THz response delay times [1,2]. We find that the formation of heavy bands is controlled by an exponentially enhanced, high-energy Kondo scale once the crystal-electric-field states become thermally occupied. We corroborate these observations by temperature-dependent, high-resolution dynamical mean-field calculations for the multi-orbital Anderson lattice model and discuss the relevance for quantum critical scenarios. |
Wednesday, March 6, 2019 11:51AM - 12:03PM |
L06.00004: Kondo effects in α and γ phases of Ce Junwon Kim, Dong-Choon Ryu, Hongchul Choi, Kyoo Kim, Byung Il Min The Kondo effect is one of the fascinating correlation phenomena in condensed matter physics. The monoatomic compound Ce, which is famous for the α - γ phase transition and the extremely rich phase diagram with at least seven allotropes, is a good sample for observing the Kondo effect and its change with respect to the temperature or pressure variations. In this research, we focused on the Kondo physics in α and γ phase among the various phases of Ce. To capture the Kondo physics, we used the first principles Dynamical Mean-Field Theory (DFMT) approach combined with Density Functional Theory (DFT)[1,2]. Unlike the cases of using DFT only, we have observed in the DFT+DMFT scheme that Kondo resonances are formed distinctly for α and γ phases of Ce, which yields different band structures between two phases, especially at around EF. We theoretically discuss the temperature-dependent physical properties of both phases, and compare their band structures with photoemission experimental results. |
Wednesday, March 6, 2019 12:03PM - 12:15PM |
L06.00005: Magnetic complexity in RScT (R=Gd, Pr, T=Sb, Ge) based compound Arjun Pathak, Francois Guillou, Yaroslav Mudryk, Vitalij K Pecharsky Ternary RTX intermetallics, where R = rare earth, T = transition metal, X = p-block element, are structurally and magnetically diverse and are among the most interesting intermetallic compounds to explore (Gupta et. al. JALCOM 618 (2015) 562). For example, GdScGe crystallizes in tetragonal CeScSi-type structure and undergoes paramagnetic to ferromagnetic (FM) transition at TC = 350K, while PrScGe (same CeScSi-structure type) has an antiferromagnetic (AFM) transition at TN = 140K followed by a second AFM transition at TN = 88K and then FM transition at TC = 80K. When germanium is replaced by antimony, the GdScSb compound crystallizes in a closely related tetragonal CeFeSi-type and orders AFM at TN ~55K. Here we present a systematic study of the interplay between crystal structure and magnetism in Gd1-xPrxScGe and GdSc(Ge1-xSbx). The substitution of heavy lanthanide, Gd, with light lanthanide, Pr, results in a complex magnetic ground state with a large exchange bias of HE ~ 1.06 kOe at T = 2K. |
Wednesday, March 6, 2019 12:15PM - 12:27PM |
L06.00006: The Ho6Mo4Al43 structure type as a cage for Uranium and Plutonium Kevin Huang, William Nelson, Alexander Chemey, Thomas Albrecht-Schmitt, Ryan Baumbach Single crystals of A6W4Al43 (A=U/Pu) were synthesized for the first time using a molten Al flux. This structure features large lattice constants (a≈10.97, c≈17.71Å) and cage-like W-Al polyhedra that surround the A ions. XRD suggests that, unlike for some other cage-like structures, the A ions do not exhibit soft lattice modes. Magnetic susceptibility measurements for U6W4Al43 show Curie-Weiss behavior, where fits to the data yield an effective magnetic moment near 2.0 µB/U. At low-T the magnetic susceptibility deviates from the Curie-Weiss law and saturates to a constant value, as seen for other spin fluctuating materials. There is evidence from the electrical transport and heat capacity for the formation of a heavy Fermi liquid ground state due to Kondo lattice behavior. In contrast, Pu6W4Al43 exhibits nearly T-independent Pauli paramagnetism, suggesting delocalization of the 5f electrons. We will discuss these results in the context of the Hill plot, where both compounds are found near the inter-actinide distance that separates delocalized and localized f-electron behavior. |
Wednesday, March 6, 2019 12:27PM - 12:39PM |
L06.00007: Multiple electronic instabilities and the anomalous thermodynamics of plutonium Neil Harrison, Jonathan B Betts, Fedor Balakirev, Marcelo Jaime, Paul H Tobash Given plutonium's importance in energy production, an understanding of its anomalous electronic and thermodynamic properties is essential for its safe handling and long term storage. In common with rare earth and other actinide elements and compounds, plutonium's physical and chemical properties are determined by f-electrons, whose transformation from localized to itinerant behavior are known to drive a significant collapse in volume. However, the occurrence of a volume collapse on both reducing and increasing the temperature and its anomalously large magnitude, reaching as much as 25% at low temperatures, represent extreme departures from the behavior of other known metals. Here we discuss new magnetostriction measurements on δ Pu, made using an optical fiber Bragg grating technique adapted for use on encapsulated radiological materials, that plutonium's exceptional thermodynamic behavior with temperature derives from its f-electron shell having multiple electronic instabilities. |
Wednesday, March 6, 2019 12:39PM - 12:51PM |
L06.00008: Fermi Surface Topology and Correlation Effects in the Electronic Structure of Plutonium Roxanne Tutchton, Jian-Xin Zhu Due to its position at the boundary between the light and heavy actinides, the electronic structure of Pu has exotic physical properties that are complex and challenging to model. The difficulties in performing accurate theoretical calculations for this element stem from the liminal characteristics of Pu-5f orbital electrons and understanding the role of the fluctuating magnetism in the electronic structure. Two methods for treating the magnetic behavior in Pu are currently debated. One is the “disordered local moment” model described by density functional theory (DFT) and the other is the “valence fluctuation” model as captured by dynamical mean-field theory (DMFT). Focusing on the |
Wednesday, March 6, 2019 12:51PM - 1:03PM |
L06.00009: Isotropic Giant Magnetoresistance in URhIn5 Carsten Putzke, Eteri Svanidze, Maja Bachmann, Markus Koenig, Kent Shirer, Jonas Diaz, Tobias Foerster, Andreas Leithe-Jasper, Eric Bauer, Filip Ronning, Yuri Grin, Philip Moll We will show results of the resistivity anisotropy in focused ion beam (FIB)-fabricated microstructures of URhIn5 and compare them to CeRhIn5. Both systems order antiferromagnetically (AFM) at 94 K and 3.8K K , respectively. Marked differences are found in their response to magnetic field, despite their structural and electronical similarities. In CeRhIn5, the AFM order leads to an increase in the ratio of in-plane to out-of-plane resistivity with a modulation of the angle-dependent magnetoresistance. In contrast, the onset of AFM order in URhIn5 has no effect on the anisotropy of the system, but leads to a giant magnetoresistance (GMR), resembling semi-metals like Bi1 and WTe22, rather than other 115-heavy fermion systems. By performing detailed angle-dependent measurements of the magnetoresistance in the U-based system, we can show that the GMR originates mainly from orbital magnetoresistance, making it unique among f-electron containing system. |
Wednesday, March 6, 2019 1:03PM - 1:15PM |
L06.00010: Large anomalous Hall effect in kagome antiferromagnet U3Ru4Al12 Tomoya Asaba, Eric Bauer, Joe D Thompson, Filip Ronning The Berry curvature in ferromagnets and antiferromagnets has been attracting huge interests due to the tunability of topological features via the magnetic structure. However, topological features in magnetic heavy fermion systems have been sparsely studied so far. In this study, we measured the anomalous Hall effect (AHE) of kagome heavy fermion antiferromagnet U3Ru4Al12. A large intrinsic AHE at high fields was observed, suggesting the presence of a large Berry curvature due to Weyl fermion. Moreover, the fields required to obtain the large Berry curvature are significantly different between B//a and B//a*, providing a mechanism to control the topological response in this system. These results may not only help to understand the topological heavy fermion physics, but also shed light on this system as an ideal playground for studying field-tuned topological states. |
Wednesday, March 6, 2019 1:15PM - 1:27PM |
L06.00011: Magnetic torque of uranium dioxide single crystals Krzysztof Gofryk, You Lai, Daniel Antonio, Ryan Baumbach, David E Graf, Marcelo Jaime, Andres Saul, Myron B Salamon, James L Smith Uranium dioxide is one of the most studied actinide compounds due to its fundamental and applied importance. Recently, we have performed a low-temperature magnetostriction study of UO2 in magnetic fields up to 95 T [Nature Comm. 8, 99 (2017)], and uncovered the appearance of linear magnetostriction, leading to a trigonal distortion and piezomagnetism (the first example of piezomagnetism in f-electron spin system). The unusually strong correlations between the magnetic moments in U-atoms and lattice distortions are a direct consequence of the non-collinear symmetry of the magnetic state that breaks time reversal symmetry in a non-trivial way that leads to the piezomagnetism. The microscopic nature of these interactions, however, remains unclear. During the talk, we will present magnetic torque measurements (up to 35 T) performed on oriented UO2 single crystals. We will discuss implications of these results in the context of the origin of the piezomagnetic ground state in this material. |
Wednesday, March 6, 2019 1:27PM - 1:39PM |
L06.00012: Magneto-acoustic Quantum Oscillations and the Fermi Surface of UPt3 Bellave Shivaram, Ludwig Holleis, Vern Ulrich We report details of magneto-acoustic quantum oscillations measured for several different angles of the magnetic field away from the a-axis as well as the c-axis in UPt3 for temperatures down to 35 mK. The effective masses of the electrons in the observed orbits obtained from the temperature dependence of the amplitudes of the oscillations will be presented. The field dependence of the frequencies of the orbits will be discussed and the low field values will be compared with the known band structure predictions of UPt3. |
Wednesday, March 6, 2019 1:39PM - 1:51PM |
L06.00013: Field Angle Tuned Metamagnetism, Lifschitz Transitions and Hidden Order in UPt3 Bellave Shivaram, Ludwig Holleis, Marcelo Jaime, John Singleton, Vern Ulrich We report ultrasound velocity measurements carried out on single crystals of UPt3, in magnetic fields, B, applied at various angles between c-axis and the basal plane. For B||c-axis, θ=90o, we observe magneto-acoustic oscillations that commence at fields as low as 12T. These oscillations suddenly break into a very large amplitude at 24.8 T implying a Lifshitz transition. Continuing to higher fields these large amplitude oscillations disappear at 30 T beyond which much smaller oscillations with altered frequencies are observed. Magnetostriction measurements performed at fields up to 65 T for θ=90o reveal small features that are consistent with boundaries at similar magnetic field values. Further, the 30 T transition appears to merge with the angle dependent metamagnetic transition at the intermediate angle θ=50o. For field along this unique angle the magnetostriction along c-axis vanishes precisely for all magnetic field values. High resolution magnetization measurements vs. field are, surprisingly, featureless and near linear when θ=90o. |
Wednesday, March 6, 2019 1:51PM - 2:03PM |
L06.00014: Anisotropic Magnetostriction Measurements in UPt3 to 65 T Bellave Shivaram, Franziska Weickert, Marcelo Jaime We present magnetostriction measurements obtained in pulsed magnetic fields upto 65 T at the NHMFL/Los Alamos in single crystals of UPt3 for field both parallel and perpendicular to the c-axis. While we reproduce published results at low fields the measurements at the highest fields for field parallel to the basal plane reveal a surprising downward trend in the magnetostriction. All these observations will be examined in the context of the single energy scale model of metamagnetism in heavy electron materials. |
Wednesday, March 6, 2019 2:03PM - 2:15PM |
L06.00015: Specific heat of Pr1-xNdxOs4Sb12 Yeh-Chia Chang, Shoji D Hishida, Pei-Chun Ho, M Brian Maple, Tatsuya Yanagisawa Filled skutterudites are the compounds that show the formula RM4X12. R is the rare earth metal, M is the transition metal, and X is the pnictogen. They will show rich varieties of strongly correlated electron behaviors, which attract our interest. The sample we focus on is a doping system, Pr1-xNdxOs4Sb12. PrOs4Sb12 show unconventional superconductivity, while NdOs4Sb12 exhibit ferromagnetism at low temperature. Therefore, there is a competition between two properties. In order to understand the compound better, we do the heat capacity measurement from 11K to 300K. From the curve of the specific heat of Pr1-xNdxOs4Sb12, parameters can be extracted out by the curve fitting with a combination of the Debye, Einstein, and Sommerfeld models. These parameters include Debye temperature, Einstein temperature, and electronic specific heat coefficient and can show the properties of the materials, such as the stiffness of the crystal structure, the rattling effect of the rare earth metal, and electron correlation. From the data analysis, we try to find out the trend of parameters depending on Nd concentration. |
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