1
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Asaba T, Naritsuka M, Asaeda H, Kosuge Y, Ikemori S, Suetsugu S, Kasahara Y, Kohsaka Y, Terashima T, Daido A, Yanase Y, Matsuda Y. Evidence for a finite-momentum Cooper pair in tricolor d-wave superconducting superlattices. Nat Commun 2024; 15:3861. [PMID: 38719822 PMCID: PMC11078924 DOI: 10.1038/s41467-024-47875-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 04/09/2024] [Indexed: 05/12/2024] Open
Abstract
Fermionic superfluidity with a nontrivial Cooper-pairing, beyond the conventional Bardeen-Cooper-Schrieffer state, is a captivating field of study in quantum many-body systems. In particular, the search for superconducting states with finite-momentum pairs has long been a challenge, but establishing its existence has long suffered from the lack of an appropriate probe to reveal its momentum. Recently, it has been proposed that the nonreciprocal electron transport is the most powerful probe for the finite-momentum pairs, because it directly couples to the supercurrents. Here we reveal such a pairing state by the non-reciprocal transport on tricolor superlattices with strong spin-orbit coupling combined with broken inversion-symmetry consisting of atomically thin d-wave superconductor CeCoIn5. We find that while the second-harmonic resistance exhibits a distinct dip anomaly at the low-temperature (T)/high-magnetic field (H) corner in the HT-plane for H applied to the antinodal direction of the d-wave gap, such an anomaly is absent for H along the nodal direction. By carefully isolating extrinsic effects due to vortex dynamics, we reveal the presence of a non-reciprocal response originating from intrinsic superconducting properties characterized by finite-momentum pairs. We attribute the high-field state to the helical superconducting state, wherein the phase of the order parameter is spontaneously spatially modulated.
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Affiliation(s)
- T Asaba
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
| | - M Naritsuka
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
- RIKEN Center for Emergent Matter Science, Wako, Saitama, 351-0198, Japan
| | - H Asaeda
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kosuge
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - S Ikemori
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - S Suetsugu
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Kohsaka
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - A Daido
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Yanase
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto, 606-8502, Japan.
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2
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Liu ZY, Jin H, Zhang Y, Fan K, Guo TF, Qin HJ, Zhu LF, Yang LZ, Zhang WH, Huang B, Fu YS. Charge-density wave mediated quasi-one-dimensional Kondo lattice in stripe-phase monolayer 1T-NbSe 2. Nat Commun 2024; 15:1039. [PMID: 38310131 PMCID: PMC10838322 DOI: 10.1038/s41467-024-45335-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 01/17/2024] [Indexed: 02/05/2024] Open
Abstract
The heavy fermion physics is dictated by subtle competing exchange interactions, posing a challenge to their understanding. One-dimensional (1D) Kondo lattice model has attracted special attention in theory, because of its exact solvability and expected unusual quantum criticality. However, such experimental material systems are extremely rare. Here, we demonstrate the realization of quasi-1D Kondo lattice behavior in a monolayer van der Waals crystal NbSe2, that is driven into a stripe phase via Se-deficient line defects. Spectroscopic imaging scanning tunneling microscopy measurements and first-principles calculations indicate that the stripe-phase NbSe2 undergoes a novel charge-density wave transition, creating a matrix of local magnetic moments. The Kondo lattice behavior is manifested as a Fano resonance at the Fermi energy that prevails the entire film with a high Kondo temperature. Importantly, coherent Kondo screening occurs only in the direction of the stripes. Upon approaching defects, the Fano resonance exhibits prominent spatial 1D oscillations along the stripe direction, reminiscent of Kondo holes in a quasi-1D Kondo lattice. Our findings provide a platform for exploring anisotropic Kondo lattice behavior in the monolayer limit.
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Affiliation(s)
- Zhen-Yu Liu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Heng Jin
- Department of Physics, Beijing Normal University, Beijing, China
- Beijing Computational Science Research Center, Beijing, China
| | - Yao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Kai Fan
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Ting-Fei Guo
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Hao-Jun Qin
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Lan-Fang Zhu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Lian-Zhi Yang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Wen-Hao Zhang
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China
| | - Bing Huang
- Department of Physics, Beijing Normal University, Beijing, China.
- Beijing Computational Science Research Center, Beijing, China.
| | - Ying-Shuang Fu
- School of Physics and Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, China.
- Wuhan Institute of Quantum Technology, Wuhan, China.
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3
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Ayani CG, Pisarra M, Ibarburu IM, Garnica M, Miranda R, Calleja F, Martín F, Vázquez de Parga AL. Probing the Phase Transition to a Coherent 2D Kondo Lattice. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2303275. [PMID: 37875781 DOI: 10.1002/smll.202303275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 09/28/2023] [Indexed: 10/26/2023]
Abstract
Kondo lattices are systems with unusual electronic properties that stem from strong electron correlation, typically studied in intermetallic 3D compounds containing lanthanides or actinides. Lowering the dimensionality of the system enhances the role of electron correlations providing a new tuning knob for the search of novel properties in strongly correlated quantum matter. The realization of a 2D Kondo lattice by stacking a single-layer Mott insulator on a metallic surface is reported. The temperature of the system is steadily lowered and by using high-resolution scanning tunneling spectroscopy, the phase transition leading to the Kondo lattice is followed. Above 27 K the interaction between the Mott insulator and the metal is negligible and both keep their original electronic properties intact. Below 27 K the Kondo screening of the localized electrons in the Mott insulator begins and below 11 K the formation of a coherent quantum electronic state extended to the entire sample, i.e., the Kondo lattice, takes place. By means of density functional theory, the electronic properties of the system and its evolution with temperature are explained. The findings contribute to the exploration of unconventional states in 2D correlated materials.
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Affiliation(s)
- Cosme G Ayani
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
| | - Michele Pisarra
- Dipartimento di Física, Università della Calabria, Via P. Bucci, Cubo 30C and INFN, Sezione LNF, Gruppo collegato di Cosenza, Cubo 31C, Rende (CS), 87036, Italy
| | - Iván M Ibarburu
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
| | - Manuela Garnica
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
| | - Rodolfo Miranda
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
- IFIMAC, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
| | - Fabián Calleja
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
| | - Fernando Martín
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
- Dep. Química Módulo 13, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
| | - Amadeo L Vázquez de Parga
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- IMDEA Nanociencia, Calle Faraday 9, Cantoblanco, Madrid, 28049, Spain
- IFIMAC, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
- Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, Cantoblanco, Madrid, 28049, Spain
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4
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Kang JH, Kim J, Park TB, Choi WS, Park S, Park T. Study on superconducting properties of CeIrIn 5thin films grown via pulsed laser deposition. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:455602. [PMID: 36055248 DOI: 10.1088/1361-648x/ac8f09] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 09/01/2022] [Indexed: 06/15/2023]
Abstract
We report the growth of CeIrIn5thin films with different crystal orientations on a MgF2(001) substrate using pulsed laser deposition technique. X-ray diffraction analysis showed that the thin films were either mainlya-axis-oriented (TF1) or a combination ofa- andc-axis-oriented (TF2). The characteristic features of heavy-fermion superconductors, i.e. Kondo coherence and superconductivity, were clearly observed, where the superconducting transition temperature (Tc) and Kondo coherence temperature (Tcoh) are 0.58 K and 41 K for TF1 and 0.52 K and 37 K for TF2, respectively. The temperature dependencies of the upper critical field (Hc2) of both thin films and the CeIrIn5single crystal revealed a scaling behavior, indicating that the nature of unconventional superconductivity has not been changed in the thin film. The successful synthesis of CeIrIn5thin films is expected to open a new avenue for novel quantum phases that may have been difficult to explore in the bulk crystalline samples.
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Affiliation(s)
- Ji-Hoon Kang
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jihyun Kim
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Tae Beom Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Woo Seok Choi
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sungmin Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Tuson Park
- Department of Physics, Sungkyunkwan University, Suwon 16419, Republic of Korea
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5
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Khim S, Landaeta JF, Banda J, Bannor N, Brando M, Brydon PMR, Hafner D, Küchler R, Cardoso-Gil R, Stockert U, Mackenzie AP, Agterberg DF, Geibel C, Hassinger E. Field-induced transition within the superconducting state of CeRh 2As 2. Science 2021; 373:1012-1016. [PMID: 34446602 DOI: 10.1126/science.abe7518] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 07/23/2021] [Indexed: 11/02/2022]
Abstract
Materials with multiple superconducting phases are rare. Here, we report the discovery of two-phase unconventional superconductivity in CeRh2As2 Using thermodynamic probes, we establish that the superconducting critical field of its high-field phase is as high as 14 tesla, even though the transition temperature is only 0.26 kelvin. Furthermore, a transition between two different superconducting phases is observed in a c axis magnetic field. Local inversion-symmetry breaking at the cerium sites enables Rashba spin-orbit coupling alternating between the cerium sublayers. The staggered Rashba coupling introduces a layer degree of freedom to which the field-induced transition and high critical field seen in experiment are likely related.
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Affiliation(s)
- S Khim
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA. .,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - J F Landaeta
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - J Banda
- Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - N Bannor
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - M Brando
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - P M R Brydon
- Department of Physics and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, Dunedin 9054, New Zealand.,Department of Physics and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, Dunedin 9054, New Zealand
| | - D Hafner
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - R Küchler
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - R Cardoso-Gil
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.,Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK.,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - U Stockert
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - A P Mackenzie
- Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA.,Department of Physics and MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Otago, Dunedin 9054, New Zealand.,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.,Scottish Universities Physics Alliance, School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
| | - D F Agterberg
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.,Department of Physics, University of Wisconsin-Milwaukee, Milwaukee, WI 53201, USA
| | - C Geibel
- Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
| | - E Hassinger
- Physik Department, Technische Universität München, 85748 Garching, Germany. .,Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany.,Physik Department, Technische Universität München, 85748 Garching, Germany
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6
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Naritsuka M, Terashima T, Matsuda Y. Controlling unconventional superconductivity in artificially engineered f-electron Kondo superlattices. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:273001. [PMID: 33946054 DOI: 10.1088/1361-648x/abfdf2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 05/04/2021] [Indexed: 06/12/2023]
Abstract
Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials, including high-Tccuprates, iron pnictides, and heavy-fermion compounds. Interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures provide a new approach to this most fundamental and hotly debated subject. We have been able to use a recent state-of-the-art molecular-beam-epitaxy technique to fabricate superlattices consisting of different heavy-fermion compounds with atomic thickness. These Kondo superlattices provide a unique opportunity to study the mutual interaction between unconventional superconductivity and magnetic order through the atomic interface. Here, we design and fabricate hybrid Kondo superlattices consisting of alternating layers of superconducting CeCoIn5withd-wave pairing symmetry and nonmagnetic metal YbCoIn5or antiferromagnetic heavy fermion metals such as CeRhIn5and CeIn3. In these Kondo superlattices, superconducting heavy electrons are confined within the two-dimensional CeCoIn5block layers and interact with neighboring nonmagnetic or magnetic layers through the interface. Superconductivity is strongly influenced by local inversion symmetry breaking at the interface in CeCoIn5/YbCoIn5superlattices. The superconducting and antiferromagnetic states coexist in spatially separated layers in CeCoIn5/CeRhIn5and CeCoIn5/CeIn3superlattices, but their mutual coupling via the interface significantly modifies the superconducting and magnetic properties. The fabrication of a wide variety of hybrid superlattices paves a new way to study the relationship between unconventional superconductivity and magnetism in strongly correlated materials.
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Affiliation(s)
- M Naritsuka
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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7
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Raczkowski M, Assaad FF. Emergent Coherent Lattice Behavior in Kondo Nanosystems. PHYSICAL REVIEW LETTERS 2019; 122:097203. [PMID: 30932556 DOI: 10.1103/physrevlett.122.097203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 01/14/2019] [Indexed: 06/09/2023]
Abstract
How many magnetic moments periodically arranged on a metallic surface are needed to generate a coherent Kondo lattice behavior? We investigate this fundamental issue within the particle-hole symmetric Kondo lattice model using quantum Monte Carlo simulations. Extra magnetic atoms forming closed shells around the initial impurity induce a fast splitting of the Kondo resonance at the inner shells, which signals the formation of composite heavy-fermion bands. The onset of the hybridization gap matches well the enhancement of antiferromagnetic spin correlations in the plane perpendicular to the applied magnetic field, a genuine feature of the coherent Kondo lattice. In contrast, the outermost shell remains dominated by a local Kondo physics with spectral features resembling the single-impurity behavior.
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Affiliation(s)
- Marcin Raczkowski
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
| | - Fakher F Assaad
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany
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8
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Naritsuka M, Rosa PFS, Luo Y, Kasahara Y, Tokiwa Y, Ishii T, Miyake S, Terashima T, Shibauchi T, Ronning F, Thompson JD, Matsuda Y. Tuning the Pairing Interaction in a d-Wave Superconductor by Paramagnons Injected through Interfaces. PHYSICAL REVIEW LETTERS 2018; 120:187002. [PMID: 29775349 DOI: 10.1103/physrevlett.120.187002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Indexed: 06/08/2023]
Abstract
Unconventional superconductivity and magnetism are intertwined on a microscopic level in a wide class of materials. A new approach to this most fundamental and hotly debated issue focuses on the role of interactions between superconducting electrons and bosonic fluctuations at the interface between adjacent layers in heterostructures. Here we fabricate hybrid superlattices consisting of alternating atomic layers of the heavy-fermion superconductor CeCoIn_{5} and antiferromagnetic (AFM) metal CeRhIn_{5}, in which the AFM order can be suppressed by applying pressure. We find that the superconducting and AFM states coexist in spatially separated layers, but their mutual coupling via the interface significantly modifies the superconducting properties. An analysis of upper critical fields reveals that, upon suppressing the AFM order by applied pressure, the force binding superconducting electron pairs acquires an extreme strong-coupling nature. This demonstrates that superconducting pairing can be tuned nontrivially by magnetic fluctuations (paramagnons) injected through the interface.
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Affiliation(s)
- M Naritsuka
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - P F S Rosa
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Yongkang Luo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Y Kasahara
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Y Tokiwa
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
- Center for Electronic Correlations and Magnetism, Institute of Physics, Augsburg University, 86159 Augsburg, Germany
| | - T Ishii
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - S Miyake
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Terashima
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - T Shibauchi
- Department of Advanced Materials Science, University of Tokyo, Chiba 277-8561, Japan
| | - F Ronning
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - J D Thompson
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
| | - Y Matsuda
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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9
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Echevarria-Bonet C, Rojas DP, Espeso JI, Rodríguez Fernández J, Rodríguez Fernández L, Bauer E, Burdin S, Magalhães SG, Fernández Barquín L. Breakdown of the coherence effects and Fermi liquid behavior in YbAl 3 nanoparticles. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:135604. [PMID: 29460843 DOI: 10.1088/1361-648x/aab0c7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A change in the Kondo lattice behavior of bulk YbAl3 has been observed when the alloy is shaped into nanoparticles (≈12 nm). Measurements of the electrical resistivity show inhibited coherence effects and deviation from the standard Fermi liquid behavior (T 2-dependence). These results are interpreted as being due to the effect of the disruption of the periodicity of the array of Kondo ions provoked by the size reduction process. Additionally, the ensemble of randomly placed nanoparticles also triggers an extra source of electronic scattering at very low temperatures (≈15 K) due to quantum interference effects.
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Affiliation(s)
- C Echevarria-Bonet
- BCMaterials, Bld. Martina Casiano, UPV/EHU Science Park, 48940 Leioa, Spain. Dpto. CITIMAC, Facultad de Ciencias, Universidad de Cantabria, 39005 Santander, Spain
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10
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Yoshida T, Daido A, Yanase Y, Kawakami N. Fate of Majorana Modes in CeCoIn_{5}/YbCoIn_{5} Superlattices: A Test Bed for the Reduction of Topological Classification. PHYSICAL REVIEW LETTERS 2017; 118:147001. [PMID: 28430503 DOI: 10.1103/physrevlett.118.147001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Indexed: 06/07/2023]
Abstract
In this paper, we propose CeCoIn_{5}/YbCoIn_{5} superlattice systems as a test bed for the reduction of topological classification in free fermions. We find that the system with a quadlayer of CeCoIn_{5} shows a topological crystalline superconducting phase with the mirror Chern number eight at the noninteracting level. Furthermore, we demonstrate that in the presence of two-body interactions, gapless edge modes are no longer protected by the symmetry in the system with a quadlayer, but are protected in the system with a bilayer or trilayer. This clearly exemplifies the reduction of topological classification from Z⊕Z to Z⊕Z_{8}.
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Affiliation(s)
- Tsuneya Yoshida
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Akito Daido
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Youichi Yanase
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
| | - Norio Kawakami
- Department of Physics, Kyoto University, Kyoto 606-8502, Japan
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