1
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Johansson A. Theory of spin and orbital Edelstein effects. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:423002. [PMID: 38955339 DOI: 10.1088/1361-648x/ad5e2b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2024] [Accepted: 07/01/2024] [Indexed: 07/04/2024]
Abstract
In systems with broken spatial inversion symmetry, such as surfaces, interfaces, or bulk systems lacking an inversion center, the application of a charge current can generate finite spin and orbital densities associated with a nonequilibrium magnetization, which is known as spin and orbital Edelstein effect (SEE and OEE), respectively. Early reports on this current-induced magnetization focus on two-dimensional Rashba systems, in which an in-plane nonequilibrium spin density is generated perpendicular to the applied charge current. However, until today, a large variety of materials have been theoretically predicted and experimentally demonstrated to exhibit a sizeable Edelstein effect, which comprises contributions from the spin as well as the orbital degrees of freedom, and whose associated magnetization may be out of plane, nonorthogonal, and even parallel to the applied charge current, depending on the system's particular symmetries. In this review, we give an overview on the most commonly used theoretical approaches for the discussion and prediction of the SEE and OEE. Further, we introduce a selection of the most intensely discussed materials exhibiting a finite Edelstein effect, and give a brief summary of common experimental techniques.
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Affiliation(s)
- Annika Johansson
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120 Halle (Saale), Germany
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2
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Dong J, Liu Y, Li Z, Xie H, Jiang Y, Wang H, Tan XY, Suwardi A, Zhou X, Li JF, Wolverton C, Dravid VP, Yan Q, Kanatzidis MG. High Thermoelectric Performance in Rhombohedral GeSe-LiBiTe 2. J Am Chem Soc 2024; 146:17355-17364. [PMID: 38870542 DOI: 10.1021/jacs.4c04453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2024]
Abstract
GeSe, an analogue of SnSe, shows promise in exhibiting exceptional thermoelectric performance in the Pnma phase. The constraints on its dopability, however, pose challenges in attaining optimal carrier concentrations and improving ZT values. This study demonstrates a crystal structure evolution strategy for achieving highly doped samples and promising ZTs in GeSe via LiBiTe2 alloying. A rhombohedral phase (R3m) can be stabilized in the GeSe-LiBiTe2 system, further evolving into a cubic (Fm3̅m) phase with a rising temperature. The band structures of GeSe-LiBiTe2 in the rhombohedral and cubic phases feature a similar multiple-valley energy-converged valence band of L and Σ bands. The observed high carrier concentration (∼1020 cm-3) reflects the effective convergence of these bands, enabling a high density-of-states effective mass and an enhanced power factor. Moreover, a very low lattice thermal conductivity of 0.6-0.5 W m-1 K-1 from 300 to 723 K is achieved in 0.9GeSe-0.1LiBiTe2, approaching the amorphous limit value. This remarkably low lattice thermal conductivity is related to phonon scattering from point defects, planar vacancies, and ferroelectric instability-induced low-energy Einstein oscillators. Finally, a maximum ZT value of 1.1 to 1.3 at 723 K is obtained, with a high average ZT value of over 0.8 (400-723 K) in 0.9GeSe-0.1LiBiTe2 samples. This study establishes a viable route for tailoring crystal structures to significantly improve the performance of GeSe-related compounds.
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Affiliation(s)
- Jinfeng Dong
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
| | - Yukun Liu
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Zhi Li
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Hongyao Xie
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
- School of Materials Science and Engineering, Beihang University, Beijing, 100191, China
| | - Yilin Jiang
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Honghui Wang
- College of Physics and Center of Quantum Materials & Devices, Chongqing University, Chongqing 401331, China
| | - Xian Yi Tan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Institute of Materials Research and Engineering, A*STAR, Singapore 138634, Singapore
| | - Ady Suwardi
- Department of Electronic Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong SAR, China
| | - Xiaoyuan Zhou
- College of Physics and Center of Quantum Materials & Devices, Chongqing University, Chongqing 401331, China
| | - Jing-Feng Li
- State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084, China
| | - Christopher Wolverton
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Vinayak P Dravid
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, United States
| | - Qingyu Yan
- School of Materials Science and Engineering, Nanyang Technological University, Singapore 639798, Singapore
- Institute of Materials Research and Engineering, A*STAR, Singapore 138634, Singapore
| | - Mercouri G Kanatzidis
- Department of Chemistry, Northwestern University, Evanston, Illinois 60208, United States
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3
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Watanabe H, Yanase Y. Magnetic parity violation and parity-time-reversal-symmetric magnets. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:373001. [PMID: 38899401 DOI: 10.1088/1361-648x/ad52dd] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024]
Abstract
Parity-time-reversal symmetry (PTsymmetry), a symmetry for the combined operations of space inversion (P) and time reversal (T), is a fundamental concept of physics and characterizes the functionality of materials as well asPandTsymmetries. In particular, thePT-symmetric systems can be found in the centrosymmetric crystals undergoing the parity-violating magnetic order which we call the odd-parity magnetic multipole order. While this spontaneous order leavesPTsymmetry intact, the simultaneous violation ofPandTsymmetries gives rise to various emergent responses that are qualitatively different from those allowed by the nonmagneticP-symmetry breaking or by the ferromagnetic order. In this review, we introduce candidates hosting the intriguing spontaneous order and overview the characteristic physical responses. Various off-diagonal and/or nonreciprocal responses are identified, which are closely related to the unusual electronic structures such as hidden spin-momentum locking and asymmetric band dispersion.
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Affiliation(s)
- Hikaru Watanabe
- Research Center for Advanced Science and Technology, University of Tokyo, Meguro-ku, Tokyo 153-8904, Japan
| | - Youichi Yanase
- Department of Physics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
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4
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Chassot F, Pulkkinen A, Kremer G, Zakusylo T, Krizman G, Hajlaoui M, Dil JH, Krempaský J, Minár J, Springholz G, Monney C. Persistence of Structural Distortion and Bulk Band Rashba Splitting in SnTe above Its Ferroelectric Critical Temperature. NANO LETTERS 2024; 24:82-88. [PMID: 38109843 PMCID: PMC10786156 DOI: 10.1021/acs.nanolett.3c03280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/20/2023]
Abstract
The ferroelectric semiconductor α-SnTe has been regarded as a topological crystalline insulator, and the dispersion of its surface states has been intensively measured with angle-resolved photoemission spectroscopy (ARPES) over the past decade. However, much less attention has been given to the impact of the ferroelectric transition on its electronic structure, and in particular on its bulk states. Here, we investigate the low-energy electronic structure of α-SnTe with ARPES and follow the evolution of the bulk-state Rashba splitting as a function of temperature, across its ferroelectric critical temperature of about Tc ≈ 110 K. Unexpectedly, we observe a persistent band splitting up to room temperature, which is consistent with an order-disorder contribution of local dipoles to the phase transition that requires the presence of fluctuating dipoles above Tc. We conclude that no topological surface state can occur under these conditions at the (111) surface of SnTe, at odds with recent literature.
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Affiliation(s)
- Frédéric Chassot
- Department
of Physics and Fribourg Center for Nanomaterials, Université de Fribourg, Fribourg 1700, Switzerland
| | - Aki Pulkkinen
- Department
of Physics and Fribourg Center for Nanomaterials, Université de Fribourg, Fribourg 1700, Switzerland
- New
Technologies-Research Center, University
of West Bohemia, Plzeň 301 00, Czech Republic
| | - Geoffroy Kremer
- Department
of Physics and Fribourg Center for Nanomaterials, Université de Fribourg, Fribourg 1700, Switzerland
- Institut
Jean Lamour, UMR 7198, CNRS-Université de Lorraine,
Campus ARTEM, 2 allée
André Guinier, BP 50840, Nancy 54011, France
| | - Tetiana Zakusylo
- Institut
für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, Linz 4040, Austria
| | - Gauthier Krizman
- Institut
für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, Linz 4040, Austria
| | - Mahdi Hajlaoui
- Institut
für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, Linz 4040, Austria
| | - J. Hugo Dil
- Institute
of Physics, Ecole Polytechnique Fédérale
de Lausanne, Lausanne 1015, Switzerland
- Photon
Science
Division, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Juraj Krempaský
- Photon
Science
Division, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Ján Minár
- New
Technologies-Research Center, University
of West Bohemia, Plzeň 301 00, Czech Republic
| | - Gunther Springholz
- Institut
für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, Linz 4040, Austria
| | - Claude Monney
- Department
of Physics and Fribourg Center for Nanomaterials, Université de Fribourg, Fribourg 1700, Switzerland
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5
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Krempaský J, Springholz G, D'Souza SW, Caha O, Gmitra M, Ney A, Vaz CAF, Piamonteze C, Fanciulli M, Kriegner D, Krieger JA, Prokscha T, Salman Z, Minár J, Dil JH. Efficient magnetic switching in a correlated spin glass. Nat Commun 2023; 14:6127. [PMID: 37779120 PMCID: PMC10543544 DOI: 10.1038/s41467-023-41718-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2023] [Accepted: 09/15/2023] [Indexed: 10/03/2023] Open
Abstract
The interplay between spin-orbit interaction and magnetic order is one of the most active research fields in condensed matter physics and drives the search for materials with novel, and tunable, magnetic and spin properties. Here we report on a variety of unique and unexpected observations in thin multiferroic Ge1-xMnxTe films. The ferrimagnetic order parameter in this ferroelectric semiconductor is found to switch direction under magnetostochastic resonance with current pulses many orders of magnitude lower as for typical spin-orbit torque systems. Upon a switching event, the magnetic order spreads coherently and collectively over macroscopic distances through a correlated spin-glass state. Utilizing these observations, we apply a novel methodology to controllably harness this stochastic magnetization dynamics.
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Affiliation(s)
- Juraj Krempaský
- Photon Science Division, Paul Scherrer Institut, CH-5232, Villigen, Switzerland.
| | - Gunther Springholz
- Institut für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, A-4040, Linz, Austria
| | | | - Ondřej Caha
- Dept. of Condensed Matter Physics, Masaryk University, Kotlářská 267/2, 61137, Brno, Czech Republic
| | - Martin Gmitra
- Institute of Physics, P. J. Šafárik University in Košice, Park Angelinum 9, 040 01, Košice, Slovakia
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01, Košice, Slovakia
| | - Andreas Ney
- Institut für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, A-4040, Linz, Austria
| | - C A F Vaz
- Photon Science Division, Paul Scherrer Institut, CH-5232, Villigen, Switzerland
| | - Cinthia Piamonteze
- Photon Science Division, Paul Scherrer Institut, CH-5232, Villigen, Switzerland
| | - Mauro Fanciulli
- LPMS, CY Cergy Paris Université, 95031, Cergy-Pontoise, France
| | - Dominik Kriegner
- Institute of Physics ASCR, v.v.i., Cukrovarnická 10, 162 53, Praha 6, Czech Republic
- Dept. of Condensed Matter Physics, Charles University, Ke Karlovu 5, 121 16, Praha 2, Czech Republic
| | - Jonas A Krieger
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
- Max Planck Institut für Mikrostrukturphysik, Weinberg 2, 06120, Halle, Germany
| | - Thomas Prokscha
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Zaher Salman
- Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute, CH-5232, Villigen PSI, Switzerland
| | - Jan Minár
- New Technologies-Research Center University of West Bohemia, Plzeň, Czech Republic.
| | - J Hugo Dil
- Photon Science Division, Paul Scherrer Institut, CH-5232, Villigen, Switzerland.
- Institut de Physique, École Polytechnique Fédérale de Lausanne, CH-1015, Lausanne, Switzerland.
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6
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Popescu DG, Husanu MA, Constantinou PC, Filip LD, Trupina L, Bucur CI, Pasuk I, Chirila C, Hrib LM, Stancu V, Pintilie L, Schmitt T, Teodorescu CM, Strocov VN. Experimental Band Structure of Pb(Zr,Ti)O 3 : Mechanism of Ferroelectric Stabilization. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2205476. [PMID: 36592417 PMCID: PMC9951575 DOI: 10.1002/advs.202205476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/07/2022] [Indexed: 06/17/2023]
Abstract
Pb(Zr,Ti)O3 (PZT) is the most common ferroelectric (FE) material widely used in solid-state technology. Despite intense studies of PZT over decades, its intrinsic band structure, electron energy depending on 3D momentum k, is still unknown. Here, Pb(Zr0.2 Ti0.8 )O3 using soft-X-ray angle-resolved photoelectron spectroscopy (ARPES) is explored. The enhanced photoelectron escape depth in this photon energy range allows sharp intrinsic definition of the out-of-plane momentum k and thereby of the full 3D band structure. Furthermore, the problem of sample charging due to the inherently insulating nature of PZT is solved by using thin-film PZT samples, where a thickness-induced self-doping results in their heavy doping. For the first time, the soft-X-ray ARPES experiments deliver the intrinsic 3D band structure of PZT as well as the FE-polarization dependent electrostatic potential profile across the PZT film deposited on SrTiO3 and Lax SrMn1- x O3 substrates. The negative charges near the surface, required to stabilize the FE state pointing away from the sample (P+), are identified as oxygen vacancies creating localized in-gap states below the Fermi energy. For the opposite polarization state (P-), the positive charges near the surface are identified as cation vacancies resulting from non-ideal stoichiometry of the PZT film as deduced from quantitative XPS measurements.
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Affiliation(s)
| | | | | | - Lucian Dragos Filip
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Lucian Trupina
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | | | - Iuliana Pasuk
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Cristina Chirila
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | | | - Viorica Stancu
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Lucian Pintilie
- National Institute of Materials PhysicsAtomistilor 405AMagurele077125Romania
| | - Thorsten Schmitt
- Swiss Light SourcePaul Scherrer InstituteVilligen‐PSI5232Switzerland
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7
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Zheng JD, Zhao YF, Hu H, Shen YH, Tan YF, Tong WY, Xiang PH, Zhong N, Yue FY, Duan CG. Ferroelectric control of pseudospin texture in CuInP 2S 6monolayer. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:204001. [PMID: 35193130 DOI: 10.1088/1361-648x/ac577d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/22/2022] [Indexed: 06/14/2023]
Abstract
Spin-orbit coupling (SOC) plays an important role in condensed matter physics and has potential applications in spintronics devices. In this paper, we study the electronic properties of ferroelectric CuInP2S6(CIPS) monolayer through first-principles calculations. The result shows that CIPS monolayer is a potential for valleytronics material and we find that the in-plane helical and nonhelical pseudospin texture are induced by the Rashba and Dresselhaus effect, respectively. The chirality of helical pseudospin texture is coupled to the out-of-plane ferroelectric polarization. Furthermore, a large spin splitting due to the SOC effect can be found atKvalley, which can be regarded as the Zeeman effect under a valley-dependent pseudomagnetic field. The CIPS monolayer with Rashbaet aleffects provides a good platform for electrically controlled spin polarization physics.
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Affiliation(s)
- Jun-Ding Zheng
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Yi-Feng Zhao
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - He Hu
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Yu-Hao Shen
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Yi-Fan Tan
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Wen-Yi Tong
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Ping-Hua Xiang
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Ni Zhong
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Fang-Yu Yue
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
| | - Chun-Gang Duan
- Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, Department of Electronics, East China Normal University, Shanghai, 200241, People's Republic of China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, People's Republic of China
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8
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Shikin AM, Rybkina AA, Estyunin DA, Klimovskikh II, Rybkin AG, Filnov SO, Koroleva AV, Shevchenko EV, Likholetova MV, Voroshnin VY, Petukhov AE, Kokh KA, Tereshchenko OE, Petaccia L, Di Santo G, Kumar S, Kimura A, Skirdkov PN, Zvezdin KA, Zvezdin AK. Non-monotonic variation of the Kramers point band gap with increasing magnetic doping in BiTeI. Sci Rep 2021; 11:23332. [PMID: 34857800 PMCID: PMC8639783 DOI: 10.1038/s41598-021-02493-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 10/27/2021] [Indexed: 12/01/2022] Open
Abstract
Polar Rashba-type semiconductor BiTeI doped with magnetic elements constitutes one of the most promising platforms for the future development of spintronics and quantum computing thanks to the combination of strong spin-orbit coupling and internal ferromagnetic ordering. The latter originates from magnetic impurities and is able to open an energy gap at the Kramers point (KP gap) of the Rashba bands. In the current work using angle-resolved photoemission spectroscopy (ARPES) we show that the KP gap depends non-monotonically on the doping level in case of V-doped BiTeI. We observe that the gap increases with V concentration until it reaches 3% and then starts to mitigate. Moreover, we find that the saturation magnetisation of samples under applied magnetic field studied by superconducting quantum interference device (SQUID) magnetometer has a similar behaviour with the doping level. Theoretical analysis shows that the non-monotonic behavior can be explained by the increase of antiferromagnetic coupled atoms of magnetic impurity above a certain doping level. This leads to the reduction of the total magnetic moment in the domains and thus to the mitigation of the KP gap as observed in the experiment. These findings provide further insight in the creation of internal magnetic ordering and consequent KP gap opening in magnetically-doped Rashba-type semiconductors.
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Affiliation(s)
- A M Shikin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.
| | - A A Rybkina
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - D A Estyunin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - I I Klimovskikh
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - A G Rybkin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - S O Filnov
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - A V Koroleva
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - E V Shevchenko
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - M V Likholetova
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - V Yu Voroshnin
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Helmholtz-Zentrum Berlin für Materialien und Energie, BESSY II, 12489, Berlin, Germany
| | - A E Petukhov
- Saint Petersburg State University, Saint Petersburg, 198504, Russia
| | - K A Kokh
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Kemerovo State University, Kemerovo, 650000, Russia.,Sobolev Institute of Geology and Mineralogy SB RAS, Novosibirsk, 630090, Russia
| | - O E Tereshchenko
- Saint Petersburg State University, Saint Petersburg, 198504, Russia.,Novosibirsk State University, Novosibirsk, 630090, Russia.,A. V. Rzhanov Institute of Semiconductor Physics, Novosibirsk, 630090, Russia
| | - L Petaccia
- Elettra Sincrotrone Trieste, 34149, Trieste, Italy
| | - G Di Santo
- Elettra Sincrotrone Trieste, 34149, Trieste, Italy
| | - S Kumar
- Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima, Hiroshima, 739-0046, Japan
| | - A Kimura
- Graduate School of Science, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - P N Skirdkov
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - K A Zvezdin
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,Moscow Institute of Physics and Technology, Dolgoprudny, 141700, Russia
| | - A K Zvezdin
- Prokhorov General Physics Institute of the Russian Academy of Sciences, Moscow, 119991, Russia.,P.N. Lebedev Physical Institute of Russian Academy of Sciences, Moscow, 119991, Russia
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9
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Krempaský J, Nicolaï L, Gmitra M, Chen H, Fanciulli M, Guedes EB, Caputo M, Radović M, Volobuev VV, Caha O, Springholz G, Minár J, Dil JH. Triple-Point Fermions in Ferroelectric GeTe. PHYSICAL REVIEW LETTERS 2021; 126:206403. [PMID: 34110214 DOI: 10.1103/physrevlett.126.206403] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 02/16/2021] [Accepted: 04/08/2021] [Indexed: 06/12/2023]
Abstract
Ferroelectric α-GeTe is unveiled to exhibit an intriguing multiple nontrivial topology of the electronic band structure due to the existence of triple-point and type-II Weyl fermions, which goes well beyond the giant Rashba spin splitting controlled by external fields as previously reported. Using spin- and angle-resolved photoemission spectroscopy combined with ab initio density functional theory, the unique spin texture around the triple point caused by the crossing of one spin-degenerate and two spin-split bands along the ferroelectric crystal axis is derived. This consistently reveals spin winding numbers that are coupled with time-reversal symmetry and Lorentz invariance, which are found to be equal for both triple-point pairs in the Brillouin zone. The rich manifold of effects opens up promising perspectives for studying nontrivial phenomena and multicomponent fermions in condensed matter systems.
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Affiliation(s)
- Juraj Krempaský
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Laurent Nicolaï
- New Technologies-Research Center, University of West Bohemia, 301 00 Plzeň 3, Czech Republic
| | - Martin Gmitra
- Institute of Physics, P. J. Šafárik University in Košice, Park Angelinum 9, 040 01 Košice, Slovakia
| | - Houke Chen
- Department of Physics, Tsinghua University, Beijing 100084, China
| | - Mauro Fanciulli
- Laboratoire de Physique des Matériaux et Surfaces, CY Cergy Paris Université, 95031 Cergy-Pontoise, France
| | - Eduardo B Guedes
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Marco Caputo
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Milan Radović
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
| | - Valentine V Volobuev
- International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences, Aleja Lotnikow 32/46, PL-02668 Warsaw, Poland
- National Technical University "KhPI", Kyrpychova Street 2, 61002 Kharkiv, Ukraine
| | - Ondřej Caha
- Department of Condensed Matter Physics, Masaryk University, Kotlářská 267/2, 61137 Brno, Czech Republic
| | - Gunther Springholz
- Institut für Halbleiter-und Festkörperphysik, Johannes Kepler Universität, A-4040 Linz, Austria
| | - Jan Minár
- New Technologies-Research Center, University of West Bohemia, 301 00 Plzeň 3, Czech Republic
| | - J Hugo Dil
- Photon Science Division, Paul Scherrer Institut, CH-5232 Villigen, Switzerland
- Institut de Physique, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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10
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Yang X, Li XM, Li Y, Li Y, Sun R, Liu JN, Bai X, Li N, Xie ZK, Su L, Gong ZZ, Zhang XQ, He W, Cheng Z. Three-Dimensional Limit of Bulk Rashba Effect in Ferroelectric Semiconductor GeTe. NANO LETTERS 2021; 21:77-83. [PMID: 33263408 DOI: 10.1021/acs.nanolett.0c03161] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Ferroelectric Rashba semiconductors (FERSCs) have recently attracted intensive attention due to their giant bulk Rashba parameter, αR, which results in a locking between the spin degrees of freedom and the switchable electric polarization. However, the integration of FERSCs into microelectronic devices has provoked questions concerning whether the Rashba effect can persist when the material thickness is reduced to several nanometers. Here we find that αR can keep a large value of 2.12 eV Å in the 5.0 nm thick GeTe film. The behavior of αR with thickness can be expressed by the scaling law and provides a 3D thickness limit of the bulk Rashba effect, dc = 2.1 ± 0.5 nm. Finally, we find that the thickness can modify the Berry curvature as well, which influences the polarization and consequently alters the αR. Our results give insight into understanding the factors influencing αR in FERSCs and pave a novel route for designing Rashba-type quantum materials.
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Affiliation(s)
- Xu Yang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Mei Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yang Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Rui Sun
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jia-Nan Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xuedong Bai
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
| | - Na Li
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zong-Kai Xie
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lei Su
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zi-Zhao Gong
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiang-Qun Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Wei He
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhaohua Cheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China
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11
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Du EW, Gong SJ, Tang X, Chu J, Rappe AM, Gong C. Ferroelectric Switching of Pure Spin Polarization in Two-Dimensional Electron Gas. NANO LETTERS 2020; 20:7230-7236. [PMID: 32786931 DOI: 10.1021/acs.nanolett.0c02584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Two-dimensional electron gas (2DEG) created at compound interfaces can exhibit a broad range of exotic physical phenomena, including quantum Hall phase, emergent ferromagnetism, and superconductivity. Although electron spin plays key roles in these phenomena, the fundamental understanding and application prospects of such emergent interfacial states have been largely impeded by the lack of purely spin-polarized 2DEG. In this work, by first-principles calculations of the multiferroic superlattice GeTe/MnTe, we find the ferroelectric polarization of GeTe is concurrent with the half-metallic 2DEG at interfaces. Remarkably, the pure spin polarization of the 2DEG can be created and annihilated by polarizing and depolarizing the ferroelectrics and can be switched (between pure spin-up and pure spin-down) by flipping the ferroelectric polarization. Given the electric-field amplification effect of ferroelectric electronics, we envision multiferroic superlattices could open up new opportunities for low-power, high-efficiency spintronic devices such as spin field-effect transistors.
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Affiliation(s)
- Er-Wei Du
- Key Laboratory of Polar Materials and Devices (MOE), Department of Optoelectronics, East China Normal University, Shanghai 200241, China
| | - Shi-Jing Gong
- Key Laboratory of Polar Materials and Devices (MOE), Department of Optoelectronics, East China Normal University, Shanghai 200241, China
- Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan, Shanxi 030006, China
- Shanghai Institute of Intelligent Electronics & Systems, Fudan University, Shanghai 200433, China
| | - Xiaodong Tang
- Key Laboratory of Polar Materials and Devices (MOE), Department of Optoelectronics, East China Normal University, Shanghai 200241, China
| | - Junhao Chu
- Department of Materials Science, Fudan University, Shanghai 200433, China
| | - Andrew M Rappe
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Cheng Gong
- Department of Electrical and Computer Engineering and Quantum Technology Center, University of Maryland, College Park, Maryland 20742, United States
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12
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Vasilyev D, Medjanik K, Babenkov S, Ellguth M, Schönhense G, Elmers HJ. Relation between spin-orbit induced spin polarization, Fano-effect and circular dichroism in soft x-ray photoemission. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2020; 32:135501. [PMID: 31796649 DOI: 10.1088/1361-648x/ab5e70] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
A Feynman diagram analysis of photoemission probabilities suggests a relation between two final-state spin polarization effects, the optical spin-orientation originating from the interaction with circularly polarized light ([Formula: see text], Fano effect) and the spin polarization induced by the spin-orbit scattering ([Formula: see text], Mott effect). The analysis predicts that [Formula: see text] is proportional to the product of [Formula: see text] and the circular dichroism in the angular distribution (CDAD) of photoelectrons. To confirm this prediction, the spin polarization of photoelectrons excited by soft x-ray radiation from initial spin-degenerate bulk states of tungsten using time-of-flight momentum microscopy with parallel spin detection has been measured. By measurement of four independent photoemission intensities for two opposite spin directions and opposite photon helicity, CDAD, Fano, and Mott effect are distinguished. The results confirm the prediction from the Feynman diagram analysis.
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Affiliation(s)
- Dmitry Vasilyev
- Institut für Physik, Johannes-Gutenberg-Universität, Staudingerweg 7, 55128 Mainz, Germany
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13
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Zhou B. Ferroelectric Rashba semiconductors, AgBiP 2X 6 (X = S, Se and Te), with valley polarization: an avenue towards electric and nonvolatile control of spintronic devices. NANOSCALE 2020; 12:5533-5542. [PMID: 32091050 DOI: 10.1039/c9nr10865c] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The electric and nonvolatile control of spin in semiconductors represents a fundamental step towards novel electronic devices. In this work, using first-principles calculations we investigate the electronic properties of AgBiP2X6 (X = S, Se, and Te) monolayers, which may be a new member of ferroelectric Rashba semiconductors due to the inversion symmetry breaking arising from the ferroelectric polarization, thus allowing for the electric control of spin. The AgBiP2X6 monolayers are dynamically and thermodynamically stable up to room temperature. In the AgBiP2Te6 monolayer, the calculated band structure reveals the direct band-gap semiconducting nature in the presence of highly mobile two-dimensional electron gas near the Fermi level. The inclusion of spin-orbit coupling yields the giant Rashba-type spin splitting with a Rashba parameter of 6.5 eV Å, which is even comparable to that of some known bulk Rashba semiconductors. Except for the Rashba-type spin splitting, spin-orbit coupling together with inversion symmetry breaking also gives rise to valley polarization located at the edge of the conduction bands. The strength of the Rashba-type spin splitting and location of the conduction band minimum can be significantly tuned by applying the in-plane biaxial strain. Also, we demonstrate that these remarkable features can be retained in the presence of the BN substrate. The coexistence of the Rashba-type spin splitting (in-plane spin direction) and band splitting at the K/K' valleys (out-of-plane spin direction) makes the AgBiP2Te6 monolayer interesting for spintronics and valleytronics.
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Affiliation(s)
- Baozeng Zhou
- Tianjin Key Laboratory of Film Electronic & Communicate Devices, School of Electrical and Electronic Engineering, Tianjin University of Technology, Tianjin 300384, China.
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14
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Kriener M, Sakano M, Kamitani M, Bahramy MS, Yukawa R, Horiba K, Kumigashira H, Ishizaka K, Tokura Y, Taguchi Y. Evolution of Electronic States and Emergence of Superconductivity in the Polar Semiconductor GeTe by Doping Valence-Skipping Indium. PHYSICAL REVIEW LETTERS 2020; 124:047002. [PMID: 32058775 DOI: 10.1103/physrevlett.124.047002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Indexed: 06/10/2023]
Abstract
GeTe is a chemically simple IV-VI semiconductor which bears a rich plethora of different physical properties induced by doping and external stimuli. Here, we report a superconductor-semiconductor-superconductor transition controlled by finely-tuned In doping. Our results reveal the existence of a critical doping concentration x_{c}=0.12 in Ge_{1-x}In_{x}Te, where various properties, including structure, resistivity, charge carrier type, and the density of states, take either an extremum or change their character. At the same time, we find indications of a change in the In-valence state from In^{3+} to In^{1+} with increasing x by core-level photoemission spectroscopy, suggesting that this system is a new promising playground to probe valence fluctuations and their possible impact on structural, electronic, and thermodynamic properties of their host.
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Affiliation(s)
- M Kriener
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - M Sakano
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - M Kamitani
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - M S Bahramy
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - R Yukawa
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
| | - K Horiba
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
| | - H Kumigashira
- Photon Factory, Institute of Materials Structure Science, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki 305-0801, Japan
- Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University, Sendai 980-8577, Japan
| | - K Ishizaka
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - Y Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
- Tokyo College, University of Tokyo, Tokyo 113-8656, Japan
| | - Y Taguchi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
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15
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O. Amorim C, Gonçalves JN, Amaral JS, Amaral VS. Changing the magnetic states of an Fe/BaTiO 3 interface through crystal field effects controlled by strain. Phys Chem Chem Phys 2020; 22:18050-18059. [DOI: 10.1039/d0cp01087a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The search for better and inexpensive magnetoelectric materials is now commonplace in solid state physics, using electric field induced strain to change the multiferroic magnetic state.
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Affiliation(s)
- Carlos O. Amorim
- Physics Department and CICECO
- University of Aveiro
- 3810-193 Aveiro
- Portugal
| | - João N. Gonçalves
- Physics Department and CICECO
- University of Aveiro
- 3810-193 Aveiro
- Portugal
| | - João S. Amaral
- Physics Department and CICECO
- University of Aveiro
- 3810-193 Aveiro
- Portugal
| | - Vítor S. Amaral
- Physics Department and CICECO
- University of Aveiro
- 3810-193 Aveiro
- Portugal
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16
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Rashba-like spin splitting along three momentum directions in trigonal layered PtBi 2. Nat Commun 2019; 10:4765. [PMID: 31628366 PMCID: PMC6802102 DOI: 10.1038/s41467-019-12805-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/27/2019] [Indexed: 11/08/2022] Open
Abstract
Spin-orbit coupling (SOC) has gained much attention for its rich physical phenomena and highly promising applications in spintronic devices. The Rashba-type SOC in systems with inversion symmetry breaking is particularly attractive for spintronics applications since it allows for flexible manipulation of spin current by external electric fields. Here, we report the discovery of a giant anisotropic Rashba-like spin splitting along three momentum directions (3D Rashba-like spin splitting) with a helical spin polarization around the M points in the Brillouin zone of trigonal layered PtBi2. Due to its inversion asymmetry and reduced symmetry at the M point, Rashba-type as well as Dresselhaus-type SOC cooperatively yield a 3D spin splitting with αR ≈ 4.36 eV Å in PtBi2. The experimental realization of 3D Rashba-like spin splitting not only has fundamental interests but also paves the way to the future exploration of a new class of material with unprecedented functionalities for spintronics applications. Rashba type spin splitting – relevant for spintronics applications - is driven by inversion symmetry breaking but could so far not be realized in all momentum directions in a crystal. Here, the authors report on PtBi2 that exhibits Rashba spin splitting in all three momentum directions.
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17
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Park IH, Zhang Q, Kwon KC, Zhu Z, Yu W, Leng K, Giovanni D, Choi HS, Abdelwahab I, Xu QH, Sum TC, Loh KP. Ferroelectricity and Rashba Effect in a Two-Dimensional Dion-Jacobson Hybrid Organic-Inorganic Perovskite. J Am Chem Soc 2019; 141:15972-15976. [PMID: 31522501 DOI: 10.1021/jacs.9b07776] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Hybrid organic-inorganic perovskites (HOIPs) are a new generation of high-performance materials for solar cells and light emitting diodes. Beyond these applications, ferroelectricity and spin-related properties of HOIPs are increasingly attracting interests. The presence of strong spin-orbit coupling, allied with symmetry breaking ensured by remanent polarization, should give rise to Rashba-type splitting of electronic bands in HOIP. However, the report of both ferroelectricity and Rashba effect in HOIP is rare. Here we report the observation of robust ferroelectricity and Rashba effect in two-dimensional Dion-Jacobson perovskites.
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Affiliation(s)
- In-Hyeok Park
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Qiannan Zhang
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371 , Singapore
| | - Ki Chang Kwon
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Ziyu Zhu
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Wei Yu
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Kai Leng
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - David Giovanni
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371 , Singapore
| | - Hwa Seob Choi
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Ibrahim Abdelwahab
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Qing-Hua Xu
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
| | - Tze Chien Sum
- Division of Physics and Applied Physics, School of Physical and Mathematical Sciences , Nanyang Technological University , 21 Nanyang Link , Singapore 637371 , Singapore
| | - Kian Ping Loh
- Department of Chemistry , National University of Singapore , 3 Science Drive 3 , Singapore 117543 , Singapore
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18
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Abstract
Ferroelectric materials are used in actuators or sensors because of their non-volatile macroscopic electric polarization. GeTe is the simplest known diatomic ferroelectric endowed with exceedingly complex physics related to its crystalline, amorphous, thermoelectric, and—fairly recently discovered—topological properties, making the material potentially interesting for spintronics applications. Typically, ferroelectric materials possess random oriented domains that need poling to achieve macroscopic polarization. By using X-ray absorption fine structure spectroscopy complemented with anomalous diffraction and piezo-response force microscopy, we investigated the bulk ferroelectric structure of GeTe crystals and thin films. Both feature multi-domain structures in the form of oblique domains for films and domain colonies inside crystals. Despite these multi-domain structures which are expected to randomize the polarization direction, our experimental results show that at room temperature there is a preferential ferroelectric order remarkably consistent with theoretical predictions from ideal GeTe crystals. This robust self-poled state has high piezoelectricity and additional poling reveals persistent memory effects.
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19
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Amorim CO, Amaral JS, Gonçalves JN, Amaral VS. Electric Field Induced Room Temperature Null to High Spin State Switching: A Computational Prediction. ADVANCED THEORY AND SIMULATIONS 2019. [DOI: 10.1002/adts.201900005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Carlos O. Amorim
- Physics Department and CICECOUniversity of Aveiro 3810‐193 Aveiro Portugal
| | - João S. Amaral
- Physics Department and CICECOUniversity of Aveiro 3810‐193 Aveiro Portugal
| | - João N. Gonçalves
- Physics Department and CICECOUniversity of Aveiro 3810‐193 Aveiro Portugal
| | - Vítor S. Amaral
- Physics Department and CICECOUniversity of Aveiro 3810‐193 Aveiro Portugal
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20
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Wang LM, Qdemat A, Petracic O, Kentzinger E, Rücker U, Zheng F, Lu PH, Wei XK, Dunin-Borkowski RE, Brückel T. Manipulation of dipolar magnetism in low-dimensional iron oxide nanoparticle assemblies. Phys Chem Chem Phys 2019; 21:6171-6177. [DOI: 10.1039/c9cp00302a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Trench-patterned iron oxide nanoparticles are switched between a superspin glass and a superferromagnetic state.
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Affiliation(s)
- Li-Ming Wang
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
- Institute of High Energy Physics
| | - Asma Qdemat
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
| | - Oleg Petracic
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
| | - Emmanuel Kentzinger
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
| | - Ulrich Rücker
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
| | - Fengshan Zheng
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - Peng-Han Lu
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - Xian-Kui Wei
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - Rafal E. Dunin-Borkowski
- Ernst Ruska-Centre for Microscopy and Spectroscopy with Electrons and Peter Grünberg Institute
- Forschungszentrum Jülich GmbH
- 52425 Jülich
- Germany
| | - Thomas Brückel
- Jülich Centre for Neutron Science JCNS and Peter Grüberg Institut PGI
- JARA-FIT
- Jülich
- Germany
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21
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Yoshimi R, Yasuda K, Tsukazaki A, Takahashi KS, Kawasaki M, Tokura Y. Current-driven magnetization switching in ferromagnetic bulk Rashba semiconductor (Ge,Mn)Te. SCIENCE ADVANCES 2018; 4:eaat9989. [PMID: 30539144 PMCID: PMC6286171 DOI: 10.1126/sciadv.aat9989] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
Multiferroic materials with both ferroelectric and ferromagnetic orders provide a promising arena for the electrical manipulation of magnetization through the mutual correlation between those ferroic orders. Such a concept of multiferroics may expand to semiconductor with both broken symmetries of spatial inversion and time reversal, that is, polar ferromagnetic semiconductors. Here, we report the observation of current-driven magnetization switching in one such example, (Ge,Mn)Te thin films. The ferromagnetism caused by Mn doping opens an exchange gap in original massless Dirac band of the polar semiconductor GeTe with Rashba-type spin-split bands. The anomalous Hall conductivity is enhanced with increasing hole carrier density, indicating that the contribution of the Berry phase is maximized as the Fermi level approaches the exchange gap. By means of pulse-current injection, the electrical switching of the magnetization is observed in the (Ge,Mn)Te thin films as thick as 200 nm, pointing to the Rashba-Edelstein effect of bulk origin. The efficiency of this effect strongly depends on the Fermi-level position owing to the efficient spin accumulation at around the gap. The magnetic bulk Rashba system will be a promising platform for exploring the functional correlations among electric polarization, magnetization, and current.
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Affiliation(s)
- R. Yoshimi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
| | - K. Yasuda
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - A. Tsukazaki
- Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
| | - K. S. Takahashi
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- PRESTO, Japan Science and Technology Agency, Chiyoda-ku, Tokyo 102-0075, Japan
| | - M. Kawasaki
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
| | - Y. Tokura
- RIKEN Center for Emergent Matter Science (CEMS), Wako 351-0198, Japan
- Department of Applied Physics and Quantum-Phase Electronics Center (QPEC), University of Tokyo, Tokyo 113-8656, Japan
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22
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Rinaldi C, Varotto S, Asa M, Sławińska J, Fujii J, Vinai G, Cecchi S, Di Sante D, Calarco R, Vobornik I, Panaccione G, Picozzi S, Bertacco R. Ferroelectric Control of the Spin Texture in GeTe. NANO LETTERS 2018; 18:2751-2758. [PMID: 29380606 PMCID: PMC6994063 DOI: 10.1021/acs.nanolett.7b04829] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 01/20/2018] [Indexed: 05/27/2023]
Abstract
The electric and nonvolatile control of the spin texture in semiconductors would represent a fundamental step toward novel electronic devices combining memory and computing functionalities. Recently, GeTe has been theoretically proposed as the father compound of a new class of materials, namely ferroelectric Rashba semiconductors. They display bulk bands with giant Rashba-like splitting due to the inversion symmetry breaking arising from the ferroelectric polarization, thus allowing for the ferroelectric control of the spin. Here, we provide the experimental demonstration of the correlation between ferroelectricity and spin texture. A surface-engineering strategy is used to set two opposite predefined uniform ferroelectric polarizations, inward and outward, as monitored by piezoresponse force microscopy. Spin and angular resolved photoemission experiments show that these GeTe(111) surfaces display opposite sense of circulation of spin in bulk Rashba bands. Furthermore, we demonstrate the crafting of nonvolatile ferroelectric patterns in GeTe films at the nanoscale by using the conductive tip of an atomic force microscope. Based on the intimate link between ferroelectric polarization and spin in GeTe, ferroelectric patterning paves the way to the investigation of devices with engineered spin configurations.
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Affiliation(s)
- Christian Rinaldi
- Department
of Physics, Politecnico di Milano, 20133 Milano, Italy
- IFN-CNR,
Politecnico di Milano, 20133 Milano, Italy
| | - Sara Varotto
- Department
of Physics, Politecnico di Milano, 20133 Milano, Italy
| | - Marco Asa
- Department
of Physics, Politecnico di Milano, 20133 Milano, Italy
| | - Jagoda Sławińska
- Consiglio
Nazionale delle Ricerche CNR-SPIN, Sede
Temporanea di Chieti, c/o Univ. “G. D’Annunzio”, 66100 Chieti, Italy
| | - Jun Fujii
- CNR-IOM, Laboratorio TASC in Area Science
Park - Basovizza, 34149 Trieste, Italy
| | - Giovanni Vinai
- CNR-IOM, Laboratorio TASC in Area Science
Park - Basovizza, 34149 Trieste, Italy
| | - Stefano Cecchi
- Paul-Drude-Institut
für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Domenico Di Sante
- Institut
für Theoretische Physik und Astrophysik, Universität
Würzburg, Am Hubland
Campus Süd, Würzburg 97074, Germany
| | - Raffaella Calarco
- Paul-Drude-Institut
für Festkörperelektronik, Hausvogteiplatz 5-7, 10117 Berlin, Germany
| | - Ivana Vobornik
- CNR-IOM, Laboratorio TASC in Area Science
Park - Basovizza, 34149 Trieste, Italy
| | - Giancarlo Panaccione
- CNR-IOM, Laboratorio TASC in Area Science
Park - Basovizza, 34149 Trieste, Italy
| | - Silvia Picozzi
- Consiglio
Nazionale delle Ricerche CNR-SPIN, Sede
Temporanea di Chieti, c/o Univ. “G. D’Annunzio”, 66100 Chieti, Italy
| | - Riccardo Bertacco
- Department
of Physics, Politecnico di Milano, 20133 Milano, Italy
- IFN-CNR,
Politecnico di Milano, 20133 Milano, Italy
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23
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Electrons and Polarons at Oxide Interfaces Explored by Soft-X-Ray ARPES. SPECTROSCOPY OF COMPLEX OXIDE INTERFACES 2018. [DOI: 10.1007/978-3-319-74989-1_6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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24
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Abstract
We study a two-dimensional electron gas exchange coupled to a system of classical magnetic ions. For large Rashba spin-orbit coupling, a single electron can become self-trapped in a skyrmion spin texture self-induced in the magnetic ions system. This new quasiparticle carries electrical and topological charge as well as a large spin, and we named it as magnetic skyrmionic polaron. We study a range of parameters; temperature, exchange coupling, Rashba coupling, and magnetic field, for which the magnetic skyrmionic polaron is the fundamental state in the system. The dynamics of this quasiparticle is studied using the collective coordinate approximation, and we obtain that in the presence of an electric field the new quasiparticle shows, due to the chirality of the skyrmion, a Hall effect. Finally, we argue that the magnetic skyrmionic polarons can be found in large Rashba spin-orbit coupling semiconductors as GeMnTe.
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Affiliation(s)
- Luis Brey
- Instituto de Ciencia de Materiales de Madrid, CSIC , 28049 Cantoblanco, Spain
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25
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Bahramy MS, Ogawa N. Bulk Rashba Semiconductors and Related Quantum Phenomena. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2017; 29:1605911. [PMID: 28370556 DOI: 10.1002/adma.201605911] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/15/2017] [Indexed: 06/07/2023]
Abstract
Bithmuth tellurohalides BiTeX (X = Cl, Br and I) are model examples of bulk Rashba semiconductors, exhibiting a giant Rashba-type spin splitting among their both valence and conduction bands. Extensive spectroscopic and transport experiments combined with the state-of-the-art first-principles calculations have revealed many unique quantum phenomena emerging from the bulk Rashba effect in these systems. The novel features such as the exotic inter- and intra-band optical transitions, enhanced magneto-optical response, divergent orbital dia-/para-magnetic susceptibility and helical spin textures with a nontrivial Berry's phase in the momentum space are among the salient discoveries, all arising from this effect. Also, it is theoretically proposed and indications have been experimentally reported that bulk Rashba semiconductors such as BiTeI have the capability of becoming a topological insulator under the application of a hydrostatic pressure. Here, we overview these studies and show that BiTeX are an ideal platform to explore the next aspects of quantum matter, which could ultimately be utilized to create spintronic devices with novel functionalities.
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Affiliation(s)
- Mohammad Saeed Bahramy
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Department of Applied Physics, University of Tokyo, Tokyo, 113-8656, Japan
| | - Naoki Ogawa
- RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
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26
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Elmers HJ, Kutnyakhov D, Chernov SV, Medjanik K, Fedchenko O, Zaporozhchenko-Zymakova A, Ellguth M, Tusche C, Viefhaus J, Schönhense G. Hosting of surface states in spin-orbit induced projected bulk band gaps of W(1 1 0) and Ir(1 1 1). JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2017; 29:255001. [PMID: 28537224 DOI: 10.1088/1361-648x/aa7173] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Spin-momentum locking of surface states has attracted great interest in recent years due to envisioned technological applications in the field of spintronics. Normal metal surfaces like W(1 1 0) and Ir(1 1 1) show surface states with energy dispersions and spin-polarization textures, which are reminiscent of topologically non-trivial surface states. In order to understand this phenomenon the connection of bulk and surface states has to be explored. Using time-of-flight momentum microscopy with soft x-ray excitation, we present a comprehensive analysis of the bulk bands of W and Ir. Surface states are determined by the same method with photon excitation in the vacuum ultraviolet region. The superposition of both spectral densities reveals the hosting of surface states within the gap structure of bulk bands projected on the surface Brillouin zone. Quantitative differences in the extension of experimental and theoretical local band gaps indicate an underestimation of electron correlation effects in theory.
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Affiliation(s)
- H J Elmers
- Institut für Physik, Johannes Gutenberg-Universität, Staudingerweg 7, D-55099 Mainz, Germany
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27
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Generalov A, Otrokov MM, Chikina A, Kliemt K, Kummer K, Höppner M, Güttler M, Seiro S, Fedorov A, Schulz S, Danzenbächer S, Chulkov EV, Geibel C, Laubschat C, Dudin P, Hoesch M, Kim T, Radovic M, Shi M, Plumb NC, Krellner C, Vyalikh DV. Spin Orientation of Two-Dimensional Electrons Driven by Temperature-Tunable Competition of Spin-Orbit and Exchange-Magnetic Interactions. NANO LETTERS 2017; 17:811-820. [PMID: 28032768 DOI: 10.1021/acs.nanolett.6b04036] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Finding ways to create and control the spin-dependent properties of two-dimensional electron states (2DESs) is a major challenge for the elaboration of novel spin-based devices. Spin-orbit and exchange-magnetic interactions (SOI and EMI) are two fundamental mechanisms that enable access to the tunability of spin-dependent properties of carriers. The silicon surface of HoRh2Si2 appears to be a unique model system, where concurrent SOI and EMI can be visualized and controlled by varying the temperature. The beauty and simplicity of this system lie in the 4f moments, which act as a multiple tuning instrument on the 2DESs, as the 4f projections parallel and perpendicular to the surface order at essentially different temperatures. Here we show that the SOI locks the spins of the 2DESs exclusively in the surface plane when the 4f moments are disordered: the Rashba-Bychkov effect. When the temperature is gradually lowered and the system experiences magnetic order, the rising EMI progressively competes with the SOI leading to a fundamental change in the spin-dependent properties of the 2DESs. The spins rotate and reorient toward the out-of-plane Ho 4f moments. Our findings show that the direction of the spins and the spin-splitting of the two-dimensional electrons at the surface can be manipulated in a controlled way by using only one parameter: the temperature.
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Affiliation(s)
| | - Mikhail M Otrokov
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia
| | - Alla Chikina
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Kristin Kliemt
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt , Max-von-Laue Straße 1, D-60438 Frankfurt am Main, Germany
| | - Kurt Kummer
- European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS40220, F-38043 Grenoble Cedex 9, France
| | - Marc Höppner
- Max Planck Institute for Solid State Research, Heisenberg Straße 1, D-70569 Stuttgart, Germany
| | - Monika Güttler
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Silvia Seiro
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
| | | | - Susanne Schulz
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Steffen Danzenbächer
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | - Evgueni V Chulkov
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Tomsk State University, Lenina Av., 36, 634050 Tomsk, Russia
- Saint Petersburg State University , 198504 Saint Petersburg, Russia
| | - Christoph Geibel
- Max Planck Institute for Chemical Physics of Solids, Nöthnitzer Straße 40, D-01187 Dresden, Germany
| | - Clemens Laubschat
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
| | | | | | - Timur Kim
- Diamond Light Source, Didcot OX11 0DE, U.K
| | | | | | | | - Cornelius Krellner
- Kristall- und Materiallabor, Physikalisches Institut, Goethe-Universität Frankfurt , Max-von-Laue Straße 1, D-60438 Frankfurt am Main, Germany
| | - Denis V Vyalikh
- Departamento de Fisica de Materiales and CFM-MPC UPV/EHU, Donostia International Physics Center (DIPC) , 20080 San Sebastian, Spain
- Institute of Solid State Physics, Dresden University of Technology , Zellescher Weg 16, D-01062 Dresden, Germany
- Saint Petersburg State University , 198504 Saint Petersburg, Russia
- IKERBASQUE, Basque Foundation for Science , 48011 Bilbao, Spain
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28
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Boschker JE, Wang R, Calarco R. GeTe: a simple compound blessed with a plethora of properties. CrystEngComm 2017. [DOI: 10.1039/c7ce01040k] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
A selection from the wide range of functional properties present in the binary compound, GeTe, are reviewed is this paper.
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Affiliation(s)
- Jos E. Boschker
- Paul-Drude-Institut für Festkörperelektronik
- 10117 Berlin
- Germany
| | - Ruining Wang
- Paul-Drude-Institut für Festkörperelektronik
- 10117 Berlin
- Germany
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