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Emergence of high-mobility carriers in topological kagome bad metal Mn$_3$Sn by intense photoexcitation
Authors:
Takuya Matsuda,
Tomoya Higo,
Kenta Kuroda,
Takashi Koretsune,
Natsuki Kanda,
Yoshua Hirai,
Hanyi Peng,
Takumi Matsuo,
Cedric Bareille,
Andrey Varykhalov,
Naotaka Yoshikawa,
Jun Yoshinobu,
Takeshi Kondo,
Ryo Shimano,
Satoru Nakatsuji,
Ryusuke Matsunaga
Abstract:
Kagome-lattice materials offer novel playgrounds of exploring topologically nontrivial states of electrons under influence of many-body interactions. A noncollinear kagome antiferromagnet Mn$_3$Sn has attracted particular interest for application in spintronics owing to the large anomalous Hall effect related to the Weyl dispersion near the Fermi energy. In addition, strong electronic correlation…
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Kagome-lattice materials offer novel playgrounds of exploring topologically nontrivial states of electrons under influence of many-body interactions. A noncollinear kagome antiferromagnet Mn$_3$Sn has attracted particular interest for application in spintronics owing to the large anomalous Hall effect related to the Weyl dispersion near the Fermi energy. In addition, strong electronic correlation suggesting the Kondo physics has also been implied. However, the effect of correlation on the band topology and their interplay remains elusive. Here, we investigate nonequilibrium Hall transport in a photoexcited Mn$_3$Sn using time-resolved terahertz Faraday rotation spectroscopy. In equilibrium, Mn$_3$Sn is a bad metal close to the Mott-Ioffe-Regal limit with low carrier mobility, and thus only the anomalous Hall effect is discerned. By contrast, intense photoexcitation beyond an approximate threshold gives rise to a clear cyclotron resonance, namely the normal Hall effect, indicating the emergence of unusual carriers with 50 times lighter effective mass and 40 times less scattering. The lifetime of high-mobility carriers as long as a few tens of picoseconds and a threshold-like behavior for the pump fluence are hardly explained by contribution of photoexcited hot carriers. Instead, the emergence of unusual carriers may be accounted for by dielectric screening of the on-site Coulomb interaction by high-density delocalized photocarriers. A possible role of electronic correlation in equilibrium transport in Mn$_3$Sn beyond the single-particle picture is discussed.
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Submitted 13 November, 2024; v1 submitted 20 November, 2023;
originally announced November 2023.
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Anomalous Hall effect of light-driven three-dimensional Dirac electrons in bismuth
Authors:
Yoshua Hirai,
Naotaka Yoshikawa,
Masashi Kawaguchi,
Masamitsu Hayashi,
Shun Okumura,
Takashi Oka,
Ryo Shimano
Abstract:
Recent advancement in laser technology has opened the path toward the manipulation of functionalities in quantum materials by intense coherent light. Here, we study three-dimensional (3D) Dirac electrons driven by circularly polarized light (CPL), when the photon energy lies within the Dirac bands. As an experimental realization of this setup, we irradiate a thin film sample of elemental bismuth,…
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Recent advancement in laser technology has opened the path toward the manipulation of functionalities in quantum materials by intense coherent light. Here, we study three-dimensional (3D) Dirac electrons driven by circularly polarized light (CPL), when the photon energy lies within the Dirac bands. As an experimental realization of this setup, we irradiate a thin film sample of elemental bismuth, which is a well-known semimetal hosting 3D Dirac electrons, with mid-infrared CPL. We successfully observe the emergence of the anomalous Hall effect (AHE) via terahertz Faraday rotation that is both pump-helicity-dependent and instantaneous. We compare our experimental findings with the results of Floquet theory, which is a powerful framework for analyzing the electronic band structure driven by coherent light. The contribution from the band structures near the one-photon resonant positions to the AHE shows a field-strength dependence consistent with our experimental results. The effective Hamiltonian on which we base our model calculations also implies that a pair of "double Weyl points" emerge due to the CPL-induced hybridization between the occupied and unoccupied 3D Dirac bands. Our findings shed light on ultrafast control of material properties in nonlinear topological optics.
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Submitted 15 January, 2023;
originally announced January 2023.
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Light-induced anomalous Hall conductivity in massive 3D Dirac semimetal Co$_3$Sn$_2$S$_2$
Authors:
Naotaka Yoshikawa,
Shun Okumura,
Yoshua Hirai,
Kazuma Ogawa,
Kohei Fujiwara,
Junya Ikeda,
Akihiro Ozawa,
Takashi Koretsune,
Ryotaro Arita,
Aditi Mitra,
Atsushi Tsukazaki,
Takashi Oka,
Ryo Shimano
Abstract:
Weyl semimetals can emerge from Dirac semimetals when the time-reversal or spatial-inversion symmetries are broken. Recently, it has been proposed based on the Floquet theory that Dirac semimetals can be converted into Weyl semimetals even by shining circularly polarized light (CPL). Here we have investigated the possibility of such a Dirac-Weyl conversion by measuring the CPL-induced anomalous Ha…
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Weyl semimetals can emerge from Dirac semimetals when the time-reversal or spatial-inversion symmetries are broken. Recently, it has been proposed based on the Floquet theory that Dirac semimetals can be converted into Weyl semimetals even by shining circularly polarized light (CPL). Here we have investigated the possibility of such a Dirac-Weyl conversion by measuring the CPL-induced anomalous Hall conductivity (AHC) in a massive 3D Dirac semimetal Co$_3$Sn$_2$S$_2$ in the paramagnetic phase using ultrafast mid-infrared pump-terahertz Faraday rotation probe spectroscopy. We find that the field-strength and driving frequency dependence of the observed AHC is well accounted for by CPL-induced nonzero Berry curvature associated with the splitting of the Dirac bands as predicted by the Floquet theory. The estimated splitting of the Dirac bands reaches about 60 % of the mass gap and the calculated CPL-induced AHC quantitatively reproduces the experimental observation, demonstrating a promising route toward the realization of Floquet-Weyl states from massive Dirac semimetals.
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Submitted 2 March, 2025; v1 submitted 24 September, 2022;
originally announced September 2022.
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Ultrafast Dynamics of Intrinsic Anomalous Hall Effect in the Topological Antiferromagnet Mn3Sn
Authors:
Takuya Matsuda,
Tomoya Higo,
Takashi Koretsune,
Natsuki Kanda,
Yoshua Hirai,
Hanyi Peng,
Takumi Matsuo,
Naotaka Yoshikawa,
Ryo Shimano,
Satoru Nakatsuji,
Ryusuke Matsunaga
Abstract:
We investigate ultrafast dynamics of the anomalous Hall effect (AHE) in the topological antiferromagnet Mn3Sn with sub-100 fs time resolution. Optical pulse excitations largely elevate the electron temperature up to 700 K, and terahertz probe pulses clearly resolves ultrafast suppression of the AHE before demagnetization. The result is well reproduced by microscopic calculation of the intrinsic Be…
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We investigate ultrafast dynamics of the anomalous Hall effect (AHE) in the topological antiferromagnet Mn3Sn with sub-100 fs time resolution. Optical pulse excitations largely elevate the electron temperature up to 700 K, and terahertz probe pulses clearly resolves ultrafast suppression of the AHE before demagnetization. The result is well reproduced by microscopic calculation of the intrinsic Berry-curvature mechanism while the extrinsic contribution is clearly excluded. Our work opens a new avenue for the study of nonequilibrium AHE to identify the microscopic origin by drastic control of the electron temperature by light.
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Submitted 21 March, 2023; v1 submitted 14 June, 2022;
originally announced June 2022.
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Ruthenocuprates RuSr2(Eu,Ce)2Cu2O10: Intrinsic magnetic multilayers
Authors:
I. Zivkovic,
Y. Hirai,
B. H. Frazer,
M. Prester,
D. Drobac,
D. Ariosa,
H. Berger,
D. Pavuna,
G. Margaritondo,
I. Felner,
M. Onellion
Abstract:
We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are…
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We report ac susceptibility data on RuSr_2(Eu,Ce)_2Cu_2O_(10-y) (Ru-1222, Ce content x=0.5 and 1.0), RuSr_2GdCu_2O_8 (Ru-1212) and SrRuO_3. Both Ru-1222 (x=0.5, 1.0) sample types exhibit unexpected magnetic dynamics in low magnetic fields: logarithmic time relaxation, switching behavior, and `inverted' hysteresis loops. Neither Ru-1212 nor SrRuO_3 exhibit such magnetic dynamics. The results are interpreted as evidence of the complex magnetic order in Ru-1222. We propose a specific multilayer model to explain the data, and note that superconductivity in the ruthenocuprate is compatible with both the presence and absence of the magnetic dynamics.
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Submitted 9 October, 2001;
originally announced October 2001.
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Ruthenocuprates: Intrinsic magnetic multilayers
Authors:
I. Zivkovic,
Y. Hirai,
M. Prester,
D. Drobac,
D. Ariosa,
G. Margaritondo,
I. Felner,
B. H. Frazer,
M. Onellion
Abstract:
We report ac susceptibility measurements on polycrystalline samples of SrRuO_3 and three ruthenocuprates: superconducting RuSr_2GdCu_2O_8 (Ru-1212), superconducting RuSr_2Eu_(2-x)Ce_xCu_2O_y (Ru-1222, x=0.5) and nonsuperconducting, insulating RuSr_2Eu_(2-x)Ce_xCu_2O_z (Ru-1222, x=1.0). Ac susceptibility of both Ru-1222 compositions exhibit logarithmic time relaxation and `inverted' hysteresis lo…
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We report ac susceptibility measurements on polycrystalline samples of SrRuO_3 and three ruthenocuprates: superconducting RuSr_2GdCu_2O_8 (Ru-1212), superconducting RuSr_2Eu_(2-x)Ce_xCu_2O_y (Ru-1222, x=0.5) and nonsuperconducting, insulating RuSr_2Eu_(2-x)Ce_xCu_2O_z (Ru-1222, x=1.0). Ac susceptibility of both Ru-1222 compositions exhibit logarithmic time relaxation and `inverted' hysteresis loops. Ru-1212 samples exhibit none of these behaviors. We interpret the magnetic behavior of Ru-1222 in the framework of weakly coupled magnetic multilayers and argue that superconductivity coexists with qualitatively different magnetic behaviors.
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Submitted 19 July, 2001; v1 submitted 18 July, 2001;
originally announced July 2001.
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Superconducting Gap vs. Wave Vector: Evidence for Hot Regions on the Fermi Surface
Authors:
R. Gatt,
S. Christensen,
B. Frazer,
Y. Hirai,
T. Schmauder,
R. J. Kelley,
M. Onellion,
I. Vobornik,
L. Perfetti,
G. Margaritondo,
A. Morawski,
T. Lada,
A. Paszewin,
C. Kendziora
Abstract:
We have used angular resolved photoemission to measure the angular dependence of the superconducting gap in highly overdoped Bi2212 (Tc=65K). While the node at 45 degrees is conserved, we find substantial deviation from a first order d-wave dependence away from the node. The pairing susceptibility is peaked at special regions on the Fermi surface. Comparing these results with a detailed mapping…
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We have used angular resolved photoemission to measure the angular dependence of the superconducting gap in highly overdoped Bi2212 (Tc=65K). While the node at 45 degrees is conserved, we find substantial deviation from a first order d-wave dependence away from the node. The pairing susceptibility is peaked at special regions on the Fermi surface. Comparing these results with a detailed mapping of the Fermi surface we performed, we could measure the extension and location of these hot regions. We find the hot regions to be evenly spread about the nominal locations of hot spots. The decrease of the gap amplitude away from these hot regions follows very closely theoretical calculations within the spin fluctuation approach. These results strongly suggest that the pairing susceptibility is peaked at Q=(Pi,Pi).
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Submitted 4 June, 1999; v1 submitted 4 June, 1999;
originally announced June 1999.