Article
Multidisciplinary Sciences
Shusaku Imajo, Toshihiro Nomura, Yoshimitsu Kohama, Koichi Kindo
Summary: In this study, the authors experimentally verified the anisotropy of the FFLO state in a 2D organic superconductor using ultrasound evidence. This exotic superconducting state exhibits spatial modulation but has not been experimentally validated for its anisotropy. The researchers detected anisotropic acoustic responses above the Pauli limit, indicating that the two-dimensional FFLO state has a center-of-mass momentum parallel to the nesting vector on the Fermi surface.
NATURE COMMUNICATIONS
(2022)
Article
Optics
Daisuke Inotani, Shigehiro Yasui, Takeshi Mizushima, Muneto Nitta
Summary: A possibility of a FFLO-like state in a population-imbalanced Fermi gas with a vortex is proposed in this study. By using mathematical models, it is found that the superfluid order parameter oscillates around the vortex core in the radial direction as the population imbalance increases, covering a wide region on the phase diagram at T = 0. This inhomogeneous superfluidity can be detected through peak structures of the local polarization rate associated with the node structure of the superfluid order parameter.
Article
Optics
Taira Kawamura, Yoji Ohashi
Summary: In this study, we theoretically explore a promising route to achieve the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state in a spin-imbalanced ultracold Fermi gas. By including strong FFLO pairing fluctuations and introducing an optical lattice, we show that the FFLO state can be stabilized and overcome the competition with phase separation. These findings contribute to the further development of unconventional Fermi superfluids in cold atom physics.
Article
Multidisciplinary Sciences
K. Kinjo, M. Manago, S. Kitagawa, Z. Q. Mao, S. Yonezawa, Y. Maeno, K. Ishida
Summary: The research reveals that Sr2RuO4 provides an ideal platform for studying the physics of Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, and the characteristic nuclear magnetic resonance spectrum confirms the spatial modulation of spin density consistent with superconducting spin smecticity.
Article
Multidisciplinary Sciences
Puhua Wan, Oleksandr Zheliuk, Noah F. Q. Yuan, Xiaoli Peng, Le Zhang, Minpeng Liang, Uli Zeitler, Steffen Wiedmann, Nigel E. Hussey, Thomas T. M. Palstra, Jianting Ye
Summary: We report the discovery of an orbital FFLO state in the multilayer Ising superconductor 2H-NbSe2, which is characterized by finite-momentum Cooper pairings. Transport measurements reveal the broken translational and rotational symmetries in this state. By establishing the entire orbital FFLO phase diagram, we demonstrate the existence of this state and provide a universal mechanism for preparing orbital FFLO states in similar materials with broken inversion symmetries.
Article
Physics, Multidisciplinary
Jin-Ge Chen, Yue-Ran Shi, Ren Zhang, Kui-Yi Gao, Wei Zhang
Summary: We investigated the possibility of stabilizing an FFLO state in a two-component Fermi gas trapped in a moving two-dimensional optical lattice, finding that a finite pairing momentum can be induced perpendicular to the moving direction for nearly half filling, leading to a tilt of the total pairing momentum towards the nesting vector for an enhancement of the density of states.
Article
Multidisciplinary Sciences
Chang-woo Cho, Jian Lyu, Cheuk Yin Ng, James Jun He, Kwan To Lo, Dmitriy Chareev, Tarob A. Abdel-Baset, Mahmoud Abdel-Hafiez, Rolf Lortz
Summary: The research reveals superconductivity beyond the Pauli limit in bulk single crystals of NbS2 under a precisely parallel field alignment, suggesting the development of a Fulde-Ferrell-Larkin-Ovchinnikov state.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Taisei Kitamura, Akito Daido, Youichi Yanase
Summary: Quantum geometry plays a crucial role in superconductors, affecting the superfluid weight and the phase transition of superconductivity. In certain cases, quantum geometric contributions can lead to metastable superconducting states and FFLO superconductivity.
Article
Physics, Multidisciplinary
S. Kasahara, H. Suzuki, T. Machida, Y. Sato, Y. Ukai, H. Murayama, S. Suetsugu, Y. Kasahara, T. Shibauchi, T. Hanaguri, Y. Matsuda
Summary: Investigating the superconducting order parameter in FeSe single crystal at high magnetic fields, thermodynamic evidence for a distinct superconducting phase was provided by heat capacity and magnetic torque measurements. Spectroscopic-imaging scanning tunneling microscopy revealed the disappearance of superconducting order parameter at the surface upon entering the high-field phase, demonstrating a pinned planar node perpendicular to the magnetic field.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Zhao Huang, C. S. Ting, Jian-Xin Zhu, Shi-Zeng Lin
Summary: This study reports the existence of a gapless Higgs mode in the Fulde-Ferrell-Larkin-Ovchinnikov states. The Higgs mode associated with amplitude fluctuations of the superconducting gap is usually heavy, but in this particular state, it becomes gapless. The existence of the gapless Higgs mode is demonstrated and it is found to be more stable and detectable.
Article
Physics, Multidisciplinary
Michele Pini, Pierbiagio Pieri, Giancarlo Calvanese Strinati
Summary: In this study, the pair susceptibility of an attractive spin-polarized Fermi gas in the normal phase was calculated as a function of pair momentum. It was found that close to unitarity, there is a strong enhancement of FFLO pairing fluctuations, which could be observed experimentally as a pronounced peak in the pair-momentum distribution. The calculations were based on a self-consistent t-matrix approach and have been validated against experimental data for several thermodynamic quantities in the unitary balanced Fermi gas system.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Materials Science, Multidisciplinary
M. Pini, P. Pieri, G. Calvanese Strinati
Summary: This study analyzes the evolution of an attractive polarized two-component Fermi gas at zero temperature as its polarization is gradually decreased from full polarization to a critical polarization where superfluidity occurs. The critical polarization and the associated superfluid instability are determined using a fully self-consistent t-matrix approach at zero temperature, constructing the polarization-vs-coupling phase diagram throughout the BCS-BEC crossover. The superfluid instability can lead to either a Fulde-Ferrel-Larkin-Ovchinnikov (FFLO) phase or a standard polarized BCS phase depending on the interparticle interaction strength between the two components. The behavior of the quasiparticle parameters in the normal Fermi gas varies significantly between the two cases.
Article
Materials Science, Multidisciplinary
Tommy Kotte, Hannes Kuhne, John A. Schlueter, Gertrud Zwicknagl, J. Wosnitza
Summary: The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state was observed in the quasi-2D organic superconductor kappa-(ET)2Cu(NCS)2 under high magnetic fields beyond the Pauli limit. The nature of the superconducting transition changed from second to first order and a further transition appeared within the high-field superconducting phase. The results provide clear experimental evidence of the transformation of the FFLO order parameter into Abrikosov-like states of higher Landau levels.
Article
Crystallography
Shiori Sugiura, Hiroki Akutsu, Yasuhiro Nakazawa, Taichi Terashima, Syuma Yasuzuka, John A. Schlueter, Shinya Uji
Summary: The Fermi surface structure of a layered organic superconductor was determined through experiments and computations, with observations of characteristic oscillations in the superconducting phase attributed to a commensurability effect. The results showed that the stability of the FFLO phase is not sensitive to the in-plane field directions.
Article
Physics, Multidisciplinary
Chang-woo Cho, Cheuk Yin Ng, Chi Ho Wong, Mahmoud Abdel-Hafiez, Alexander N. Vasiliev, Dmitriy A. Chareev, A. G. Lebed, Rolf Lortz
Summary: This study compares the upper critical field behaviors of two superconductors, 2H-NbSe2 and 2H-NbS2, using magnetic torque experiments and a high-precision piezo-rotary positioner. It is found that when the layer structure is aligned parallel to the field, orbital effects significantly suppress superconductivity in NbSe2, while NbS2 forms a Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state above the Pauli limiting field. Additionally, the coherence length of NbSe2 perpendicular to the layers is much larger than the interlayer distance, leading to the suppression of superconductivity before reaching the Pauli limit, in contrast to NbS2.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Stephen Kudla, Dominique M. Gautreau, Daniel E. Sheehy
Article
Optics
Ben A. Olsen, Melissa C. Revelle, Jacob A. Fry, Daniel E. Sheehy, Randall G. Hulet
Article
Materials Science, Multidisciplinary
David J. Alspaugh, Mahmoud M. Asmar, Daniel E. Sheehy, Ilya Vekhter
Summary: We study the influence of nonhelical spin textures on the proximity-induced superconductivity in the interface states of topological insulator-superconductor heterojunctions. By calculating the conductance of lateral heterojunctions, we find that interface potentials may cause a mismatch in Fermi velocity and spin texture between the two regions. By enforcing current conservation across the interface, we derive boundary conditions and calculate the conductance in both normal and superconducting states. We find that nonzero conductance signatures only appear for certain combinations of nonhelical spin textures and parent superconducting materials in the case of spin-triplet superconductors.
Article
Optics
Anshuman Bhardwaj, Dzmitry Vaido, Daniel E. Sheehy
Summary: This theoretical study examines the dynamics of a Bose-Einstein condensate trapped inside an expanding toroid that mimics an inflationary universe. As the system expands, phonons in the BEC experience redshift and damping, leading to spontaneous particle creation and impacting atom density and density correlations. The predictions and findings in this study provide insights into connections between the dynamics of BEC and inflationary cosmological theories.
Article
Physics, Multidisciplinary
David J. Alspaugh, Daniel E. Sheehy, Mark O. Goerbig, Pascal Simon
PHYSICAL REVIEW RESEARCH
(2020)
Article
Optics
Kelly R. Patton, Daniel E. Sheehy
Article
Optics
S. Laalitya Uppalapati, Daniel E. Sheehy
Article
Materials Science, Multidisciplinary
Julia M. Link, Daniel E. Sheehy, Boris N. Narozhny, Joerg Schmalian
Article
Materials Science, Multidisciplinary
David J. Alspaugh, Mahmoud M. Asmar, Daniel E. Sheehy, Ilya Vekhter
Article
Materials Science, Multidisciplinary
Mahmoud M. Asmar, Daniel E. Sheehy, Ilya Vekhter
Article
Optics
Kelly R. Patton, Dominique M. Gautreau, Stephen Kudla, Daniel E. Sheehy
Article
Materials Science, Multidisciplinary
Julia M. Link, Peter P. Orth, Daniel E. Sheehy, Jorg Schmalian
Article
Materials Science, Multidisciplinary
Mahmoud M. Asmar, Daniel E. Sheehy, Ilya Vekhter
