The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
Liang Fu - One of the best experts on this subject based on the ideXlab platform.
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Odd Parity superconductors with two component order parameters nematic and chiral full gap and majorana node
Physical Review B, 2016Co-Authors: Jorn W F Venderbos, Vladyslav Kozii, Liang FuAbstract:Author(s): Venderbos, JWF; Kozii, V; Fu, L | Abstract: © 2016 American Physical Society. Motivated by the recent experiment indicating that superconductivity in the doped topological insulator CuxBi2Se3 has an Odd-Parity pairing symmetry with rotational symmetry breaking, we study the general class of Odd-Parity superconductors with two-component order parameters in trigonal and hexagonal crystal systems. In the presence of strong spin-orbit interaction, we find two possible superconducting phases below Tc, a time-reversal-breaking (i.e., chiral) phase and an anisotropic (i.e., nematic) phase, and determine their relative energetics from the gap function in momentum space. The nematic superconductor generally has a full quasiparticle gap, whereas the chiral superconductor with a three-dimensional (3D) Fermi surface has point nodes with lifted spin degeneracy, resulting in itinerant Majorana fermions in the bulk and topological Majorana arcs on the surface.
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Odd Parity superconductivity in the vicinity of inversion symmetry breaking in spin orbit coupled systems
Physical Review Letters, 2015Co-Authors: Vladyslav Kozii, Liang FuAbstract:We study superconductivity in spin-orbit-coupled systems in the vicinity of inversion symmetry breaking. We find that, because of the presence of spin-orbit coupling, fluctuations of the incipient Parity-breaking order generate an attractive pairing interaction in an Odd-Parity pairing channel, which competes with the s-wave pairing. We show that Coulomb repulsion or an external Zeeman field suppresses the s-wave pairing and promotes the Odd-Parity superconducting state. Our work provides a new mechanism for Odd-Parity pairing and opens a route to novel topological superconductivity.
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Odd Parity pairing and topological superconductivity in a strongly spin orbit coupled semiconductor
Physical Review Letters, 2012Co-Authors: Satoshi Sasaki, Liang Fu, A A Taskin, Kouji Segawa, Yoichi AndoAbstract:: The existence of topological superconductors preserving time-reversal symmetry was recently predicted, and they are expected to provide a solid-state realization of itinerant massless Majorana fermions and a route to topological quantum computation. Their first likely example, Cu(x)Bi(2)Se(3), was discovered last year, but the search for new materials has so far been hindered by the lack of a guiding principle. Here, we report point-contact spectroscopy experiments suggesting that the low-carrier-density superconductor Sn(1-x)In(x)Te is accompanied by surface Andreev bound states which, with the help of theoretical analysis, would give evidence for Odd-Parity pairing and topological superconductivity. The present and previous finding of possible topological superconductivity in Sn(1-x)In(x)Te and Cu(x)Bi(2)Se(3) suggests that Odd-Parity pairing favored by strong spin-orbit coupling is likely to be a common underlying mechanism for materializing topological superconductivity.
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spin orbit locking as a protection mechanism of the Odd Parity superconducting state against disorder
Physical Review Letters, 2012Co-Authors: Karen Michaeli, Liang FuAbstract:: Unconventional superconductors host a plethora of interesting physical phenomena. However, the standard theory of superconductors suggests that unconventional pairing is highly sensitive to disorder, and hence can only be observed in ultraclean systems. We find that due to an emergent chiral symmetry, spin-orbital locking can parametrically suppress pair decoherence introduced by impurity scattering in Odd-Parity superconductors. Our work demonstrates that disorder is not an obstacle to realize Odd-Parity superconductivity in materials with strong spin-orbit coupling.
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Odd Parity topological superconductors theory and application to cu _x bi _2 se _3
Physical Review Letters, 2010Co-Authors: Liang Fu, Erez BergAbstract:Topological superconductors have a full pairing gap in the bulk and gapless surface Andreev bound states. In this Letter, we provide a sufficient criterion for realizing time-reversal-invariant topological superconductors in centrosymmetric superconductors with Odd-Parity pairing. We next study the pairing symmetry of the newly discovered superconductor ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ within a two-orbital model, and find that a novel spin-triplet pairing with Odd Parity is favored by strong spin-orbit coupling. Based on our criterion, we propose that ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ is a good candidate for a topological superconductor. We close by discussing experimental signatures of this new topological phase.
Youichi Yanase - One of the best experts on this subject based on the ideXlab platform.
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multiple Odd Parity superconducting phases in bilayer transition metal dichalcogenides
arXiv: Superconductivity, 2020Co-Authors: Shota Kanasugi, Youichi YanaseAbstract:We study unconventional superconductivity in a two-dimensional locally noncentrosymmetric triangular lattice. The model is relevant to bilayer transition metal dichalcogenides with 2H$_b$ stacking structure, for example. The superconducting instability is analyzed by solving the linearized Eliashberg equation within the random phase approximation. We show that ferromagnetic fluctuations are dominant owing to the existence of disconnected Fermi pockets near van Hove singularity, and hence Odd-Parity spin-triplet superconductivity is favored. In the absence of the spin-orbit coupling, we find that Odd-Parity $f$-wave superconducting state is stabilized in a wide range of carrier density and interlayer coupling. Furthermore, we investigate impacts of the layer-dependent staggered Rashba and Zeeman spin-orbit coupling on the superconductivity. Multiple Odd-Parity superconducting phase diagrams are obtained as a function of the spin-orbit coupling and Coulomb interaction. Especially, a topological chiral $p$-wave pairing state is stabilized in the presence of a moderate Zeeman spin-orbit coupling. Our results shed light on a possibility of Odd-Parity superconductivity in various ferromagnetic van der Waals materials.
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Odd Parity multipole fluctuation and unconventional superconductivity in locally noncentrosymmetric crystal
Physical Review B, 2018Co-Authors: Jun Ishizuka, Youichi YanaseAbstract:A microscopic calculation and symmetry argument reveal superconductivity in the vicinity of Parity-violating magnetic order. An augmented cluster magnetic multipole order in a crystal lacking local space inversion Parity may break global inversion symmetry, and then, it is classified into an Odd-Parity multipole order. We investigate unconventional superconductivity induced by an Odd-Parity magnetic multipole fluctuation in a two-dimensional two-sublattice Hubbard model motivated by Sr$_2$IrO$_4$. We find that even-Parity superconductivity is more significantly suppressed by a spin-orbit coupling than that in a globally noncentrosymmetric system. Consequently, two Odd-Parity superconducting states are stabilized by magnetic multipole fluctuations in a large spin-orbit coupling region. Both of them are identified as $Z_2$ topological superconducting states. The obtained gap function of inter-sublattice pairing shows a gapped/nodal structure protected by nonsymmorphic symmetry. Our finding implies a new family of Odd-Parity topological superconductors. Candidate materials are discussed.
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Odd Parity superconductivity in bilayer transition metal dichalcogenides
Physical Review B, 2017Co-Authors: Yasuharu Nakamura, Youichi YanaseAbstract:Spin-orbit coupling in transition metal dichalcogenides (TMDCs) causes spin-valley locking giving rise to unconventional optical, transport, and superconducting properties. In this paper, we propose exotic superconductivity in bilayer group-IV TMDCs by symmetry control. The sublattice-dependent hidden spin-orbit coupling arising from local inversion symmetry breaking in the crystal structure may stabilize the Odd-Parity superconductivity by purely $s$-wave local pairing interaction. The stability of the Odd-Parity superconducting state depends on the bilayer stacking. The 2H$_b$ stacking in MoX$_2$ and WX$_2$ (X =S, Se) favors the Odd-Parity superconductivity due to interlayer quantum interference. On the other hand, the Odd-Parity superconductivity is suppressed by the 2H$_a$ stacking of NbSe$_2$. Calculating the phase diagram of the tight-binding model derived from first principles band calculations, we conclude that the intercalated bilayer MoS$_2$ and WS$_2$ are candidates for a new class of Odd-Parity superconductors by spin-orbit coupling.
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Odd Parity superconductivity by competing spin orbit coupling and orbital effect in artificial heterostructures
arXiv: Superconductivity, 2015Co-Authors: Tatsuya Watanabe, Tomohiro Yoshida, Youichi YanaseAbstract:We show that Odd-Parity superconductivity occurs in multilayer Rashba systems without requiring spin-triplet Cooper pairs. A pairing interaction in the spin-singlet channel stabilizes the Odd-Parity pair-density-wave (PDW) state in the magnetic field parallel to the two-dimensional conducting plane. It is shown that the layer-dependent Rashba spin-orbit coupling and the orbital effect play essential roles for the PDW state in binary and tricolor heterostructures. We demonstrate that the Odd-Parity PDW state is a symmetry-protected topological superconducting state characterized by the one-dimensional winding number in the symmetry class BDI. The superconductivity in the artificial heavy-fermion superlattice CeCoIn_5/YbCoIn_5 and bilayer interface SrTiO_3/LaAlO_3 is discussed.
Erez Berg - One of the best experts on this subject based on the ideXlab platform.
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Odd Parity topological superconductors theory and application to cu _x bi _2 se _3
Physical Review Letters, 2010Co-Authors: Liang Fu, Erez BergAbstract:Topological superconductors have a full pairing gap in the bulk and gapless surface Andreev bound states. In this Letter, we provide a sufficient criterion for realizing time-reversal-invariant topological superconductors in centrosymmetric superconductors with Odd-Parity pairing. We next study the pairing symmetry of the newly discovered superconductor ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ within a two-orbital model, and find that a novel spin-triplet pairing with Odd Parity is favored by strong spin-orbit coupling. Based on our criterion, we propose that ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ is a good candidate for a topological superconductor. We close by discussing experimental signatures of this new topological phase.
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Odd-Parity Topological Superconductors: Theory and Application to Cu$_x$Bi$_2$Se$_3$
Physical Review Letters, 2010Co-Authors: Liang Fu, Erez BergAbstract:Topological superconductors have a full pairing gap in the bulk and gapless surface Andreev bound states. In this Letter, we provide a sufficient criterion for realizing time-reversal-invariant topological superconductors in centrosymmetric superconductors with Odd-Parity pairing. We next study the pairing symmetry of the newly discovered superconductor ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ within a two-orbital model, and find that a novel spin-triplet pairing with Odd Parity is favored by strong spin-orbit coupling. Based on our criterion, we propose that ${\mathrm{Cu}}_{x}{\mathrm{Bi}}_{2}{\mathrm{Se}}_{3}$ is a good candidate for a topological superconductor. We close by discussing experimental signatures of this new topological phase.
Joel Saavedra - One of the best experts on this subject based on the ideXlab platform.
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nonminimal derivative coupling scalar tensor theories Odd Parity perturbations and black hole stability
Physical Review D, 2015Co-Authors: Adolfo Cisterna, Miguel Cruz, Terence Delsate, Joel SaavedraAbstract:We derive the Odd Parity perturbation equation in scalar-tensor theories with a non minimal kinetic coupling sector of the general Horndeski theory, where the kinetic term is coupled to the metric and the Einstein tensor. We derive the potential of the perturbation, by identifying a master function and switching to tortoise coordinates. We then prove the mode stability under linear Odd- Parity perturbations of hairy black holes in this sector of Horndeski theory, when a cosmological constant term in the action is included. Finally, we comment on the existence of slowly rotating black hole solutions in this setup and discuss their implications on the physics of compact objects configurations, such as neutron stars.
Das S Sarma - One of the best experts on this subject based on the ideXlab platform.
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Odd Parity superconductivity from phonon mediated pairing application to cu x bi 2 se 3
Physical Review B, 2014Co-Authors: P. M. R. Brydon, Das S SarmaAbstract:Motivated by the proposed topological state in Cu$_x$Bi$_2$Se$_3$, we study the possibility of phonon-mediated Odd-Parity superconductivity in spin-orbit coupled systems with time-reversal and inversion symmetry. For such systems, we show that, in general, pure electron-phonon coupling can never lead to a triplet state with a higher critical temperature than the leading singlet state. The Coulomb pseudopotential, which is the repulsive part of the electron-electron interaction and is typically small in weakly correlated systems, is therefore critical to stabilizing the triplet state. We introduce a chirality quantum number, which identifies the electron-phonon vertex interactions that are most favorable to the triplet channel as those that conserve chirality. Applying these results to Cu$_x$Bi$_2$Se$_3$, we find that a phonon-mediated Odd-Parity state may be realized in the presence of weak electronic correlations if the chirality-preserving electron-phonon vertices are much stronger than the chirality-flipping vertices.
