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Khaetskii A, Juričič V, Balatsky AV. Thermal magnetic fluctuations of a ferroelectric quantum critical point. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 33:04LT01. [PMID: 33146153 DOI: 10.1088/1361-648x/abbb0f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Entanglement of two different quantum orders is of an interest of the modern condensed matter physics. One of the examples is the dynamical multiferroicity, where fluctuations of electric dipoles lead to magnetization. We investigate this effect at finite temperature and demonstrate an elevated magnetic response of a ferroelectric near the ferroelectric quantum critical point (FE QCP). We calculate the magnetic susceptibility of a bulk sample on the paraelectric side of the FE QCP at finite temperature and find enhanced magnetic susceptibility near the FE QCP. We propose quantum paraelectric strontium titanate as a candidate material to search for dynamic multiferroicity. We estimate the magnitude of the magnetic susceptibility for this material and find that it is detectable experimentally.
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Affiliation(s)
- Alexander Khaetskii
- Department of Physics, University of Connecticut, Storrs, CT 06269, United States of America
| | - Vladimir Juričič
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - Alexander V Balatsky
- Department of Physics, University of Connecticut, Storrs, CT 06269, United States of America
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
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He X, Bansal D, Winn B, Chi S, Boatner L, Delaire O. Anharmonic Eigenvectors and Acoustic Phonon Disappearance in Quantum Paraelectric SrTiO_{3}. PHYSICAL REVIEW LETTERS 2020; 124:145901. [PMID: 32338961 DOI: 10.1103/physrevlett.124.145901] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 01/19/2020] [Accepted: 03/16/2020] [Indexed: 06/11/2023]
Abstract
Pronounced anomalies in the SrTiO_{3} dynamical structure factor, S(Q,E), including the disappearance of acoustic phonon branches at low temperatures, were uncovered with inelastic neutron scattering (INS) and simulations. The striking effect reflects anharmonic couplings between acoustic and optic phonons and the incipient ferroelectric instability near the quantum critical point. It is rationalized using a first-principles renormalized anharmonic phonon approach, pointing to nonlinear Ti-O hybridization causing unusual changes in real-space phonon eigenvectors, frequencies, group velocities, and scattering phase space. Our method is general and establishes how T dependences beyond the harmonic regime, assessed by INS mapping of large reciprocal-space volumes, provide real-space insights into anharmonic atomic dynamics near phase transitions.
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Affiliation(s)
- Xing He
- Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
| | - Dipanshu Bansal
- Department of Mechanical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra 400076, India
| | - Barry Winn
- Neutron Scattering Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Songxue Chi
- Neutron Scattering Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Lynn Boatner
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Olivier Delaire
- Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina 27708, USA
- Department of Physics, Duke University, Durham, North Carolina 27708, USA
- Department of Chemistry, Duke University, Durham, North Carolina 27708, USA
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Dunnett K, Zhu JX, Spaldin NA, Juričić V, Balatsky AV. Dynamic Multiferroicity of a Ferroelectric Quantum Critical Point. PHYSICAL REVIEW LETTERS 2019; 122:057208. [PMID: 30822032 DOI: 10.1103/physrevlett.122.057208] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Indexed: 06/09/2023]
Abstract
Quantum matter hosts a large variety of phases, some coexisting, some competing; when two or more orders occur together, they are often entangled and cannot be separated. Dynamical multiferroicity, where fluctuations of electric dipoles lead to magnetization, is an example where the two orders are impossible to disentangle. Here we demonstrate an elevated magnetic response of a ferroelectric near the ferroelectric quantum critical point (FE QCP), since magnetic fluctuations are entangled with ferroelectric fluctuations. We thus suggest that any ferroelectric quantum critical point is an inherent multiferroic quantum critical point. We calculate the magnetic susceptibility near the FE QCP and find a region with enhanced magnetic signatures near the FE QCP and controlled by the tuning parameter of the ferroelectric phase. The effect is small but observable-we propose quantum paraelectric strontium titanate as a candidate material where the magnitude of the induced magnetic moments can be ∼5×10^{-7} μ_{B} per unit cell near the FE QCP.
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Affiliation(s)
- K Dunnett
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - J-X Zhu
- T-4 and CINT, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - N A Spaldin
- Materials Theory, ETH Zurich, Wolfgang-Pauli-Strasse 27, CH-8093 Zürich, Switzerland
| | - V Juričić
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
| | - A V Balatsky
- Nordita, KTH Royal Institute of Technology and Stockholm University, Roslagstullsbacken 23, SE-106 91 Stockholm, Sweden
- Department of Physics, University of Connecticut, Storrs, Connecticut 06269, USA
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Kawarasaki M, Tanabe K, Terasaki I, Fujii Y, Taniguchi H. Intrinsic Enhancement of Dielectric Permittivity in (Nb + In) co-doped TiO 2 single crystals. Sci Rep 2017; 7:5351. [PMID: 28706304 PMCID: PMC5509748 DOI: 10.1038/s41598-017-05651-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 06/01/2017] [Indexed: 11/17/2022] Open
Abstract
The development of dielectric materials with colossal permittivity is important for the miniaturization of electronic devices and fabrication of high-density energy-storage devices. The electron-pinned defect-dipoles has been recently proposed to boost the permittivity of (Nb + In) co-doped TiO2 to 105. However, the follow-up studies suggest an extrinsic contribution to the colossal permittivity from thermally excited carriers. Herein, we demonstrate a marked enhancement in the permittivity of (Nb + In) co-doped TiO2 single crystals at sufficiently low temperatures such that the thermally excited carriers are frozen out and exert no influence on the dielectric response. The results indicate that the permittivity attains quadruple of that for pure TiO2. This finding suggests that the electron-pinned defect-dipoles add an extra dielectric response to that of the TiO2 host matrix. The results offer a novel approach for the development of functional dielectric materials with large permittivity by engineering complex defects into bulk materials.
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Affiliation(s)
| | - Kenji Tanabe
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Ichiro Terasaki
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan
| | - Yasuhiro Fujii
- Department of Physical Sciences, Ritsumeikan University, Kusatsu, 525-8577, Japan
| | - Hiroki Taniguchi
- Department of Physics, Nagoya University, Nagoya, 464-8602, Japan.
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Cui YT, Moore RG, Zhang AM, Tian Y, Lee JJ, Schmitt FT, Zhang WH, Li W, Yi M, Liu ZK, Hashimoto M, Zhang Y, Lu DH, Devereaux TP, Wang LL, Ma XC, Zhang QM, Xue QK, Lee DH, Shen ZX. Interface ferroelectric transition near the gap-opening temperature in a single-unit-cell FeSe film grown on Nb-Doped SrTiO3 substrate. PHYSICAL REVIEW LETTERS 2015; 114:037002. [PMID: 25659015 DOI: 10.1103/physrevlett.114.037002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Indexed: 06/04/2023]
Abstract
We report findings of strong anomalies in both mutual inductance and inelastic Raman spectroscopy measurements of single-unit-cell FeSe film grown on Nb-doped SrTiO3, which occur near the temperature where the superconductinglike energy gap opens. Analysis suggests that the anomaly is associated with a broadened ferroelectric transition in a thin layer near the FeSe/SrTiO3 interface. The coincidence of the ferroelectric transition and gap-opening temperatures adds credence to the central role played by the film-substrate interaction on the strong Cooper pairing in this system. We discuss scenarios that could explain such a coincidence.
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Affiliation(s)
- Y-T Cui
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - R G Moore
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - A-M Zhang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Y Tian
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - J J Lee
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - F T Schmitt
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - W-H Zhang
- State Key Lab of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
| | - W Li
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Yi
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Z-K Liu
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Hashimoto
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - Y Zhang
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA and Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - D-H Lu
- Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T P Devereaux
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - L-L Wang
- State Key Lab of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - X-C Ma
- State Key Lab of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Q-M Zhang
- Department of Physics, Renmin University of China, Beijing 100872, China
| | - Q-K Xue
- State Key Lab of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China and Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - D-H Lee
- Department of Physics, University of California at Berkeley, Berkeley, California 94720, USA and Material Science Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Z-X Shen
- Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
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Bussmann-Holder A. The polarizability model for ferroelectricity in perovskite oxides. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:273202. [PMID: 22718683 DOI: 10.1088/0953-8984/24/27/273202] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
This article reviews the polarizability model and its applications to ferroelectric perovskite oxides. The motivation for the introduction of the model is discussed and nonlinear oxygen ion polarizability effects and their lattice dynamical implementation outlined. While a large part of this work is dedicated to results obtained within the self-consistent-phonon approximation, nonlinear solutions of the model are also handled, which are of interest to the physics of relaxor ferroelectrics, domain wall motions, and incommensurate phase transitions. The main emphasis is to compare the results of the model with experimental data and to predict novel phenomena.
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Affiliation(s)
- Annette Bussmann-Holder
- Max-Planck-Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart, Germany.
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Wei T, Guo YY, Guo YJ, Luo SJ, Wang KF, Liu JM, Wang PW, Yu DP. Competition between quantum fluctuations and antiferroelectric order in Ru-doped Sr(0.8)Ca(0.2)Ti(1-x)Ru(x)O(3). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2009; 21:375901. [PMID: 21832355 DOI: 10.1088/0953-8984/21/37/375901] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The competition between quantum fluctuations and the antiferroelectric state in Sr(0.8)Ca(0.2)Ti(1-x)Ru(x)O(3) is investigated by measuring the low-temperature dielectric permittivity and by Raman spectroscopy. We demonstrate the significant impact of quantum fluctuations on the stability of the antiferroelectric polar order. It is revealed that the structural phase transitions can be modified by the quantum fluctuations, enhancing the stability of the high-symmetry phase and suppressing the antiferroelectric transitions. More importantly, a quantum antiferroelectric state, exhibiting similar behavior as the quantum ferroelectric state in terms of dielectric response, is identified. In addition, the effect of quantum fluctuations on the increasing permittivity at low temperature is also discussed.
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Affiliation(s)
- T Wei
- Nanjing National Laboratory of Microstructure, Nanjing University, Nanjing 210093, People's Republic of China
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