Quantum quenches and competing orders

Fu, Wenbo; Hung, Ling-Yan; Sachdev, Subir

doi:10.1103/physrevb.90.024506

Cited by 90 publications

(155 citation statements)

References 16 publications

Supporting

Mentioning

144

Contrasting

Order By: Relevance

“…[13], except h 5 . The last term corresponds to the effects of hexagonal warping in the Fermi surface of Cu x Bi 2 Se 3 [30]. We drop this term in most of our calculations, but argue the effects on the NMR rate at the end of this paper.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Inverse coherence effects in nuclear magnetic relaxation rates as a sign of topological superconductivity

2015

View full text Add to dashboard Cite

We reveal that three-dimensional multi-orbital topological superconductivity can be identified by a bulk measurement, i.e., the temperature dependence of nuclear magnetic relaxation (NMR) rates. Below a critical temperature Tc, the NMR rate in the topological state exhibits an anti-peak profile, which is opposite to the conventional s-wave state. This inversion coherence effect comes from a twist of order parameters with respect to orbital and spin degrees of freedom. Our self-consistent calculations in the model for CuxBi2Se3 prove that the inverse coherence effect appears as a concave temperature dependence of the NMR rates. We propose that a time-reversal-invariant orbitalsinglet spin-triplet topological superconductivity is characterized by the temperature dependence of the NMR rate. [17][18][19]. Among these studies, although the gapless bound states on surfaces at low temperatures are actively studied [9,11,[20][21][22], observing an intrinsic behavior via bulk measurements is rarely argued. In addition, the setups of surface measurements would be sensitively affected by the characteristics of the interfaces between materials and probes. Thus, a bulk measurement sensitive to topological characters is important for supporting results in surface measurements and revealing the properties of Cooper-pair condensations.A key quantity of connecting topological characters with bulk measurements is a correlation function. Current-current correlation functions, for example, lead to the quantized conductance in integer quantum Hall effects [5]. Spin-spin correlation functions are essential for superconductivity since these quantities well reflect the spin-state properties of Cooper pairs. Nuclear magnetic relaxation (NMR) rates (T −1 1 ) are directly related to the spin-spin correlation functions. Therefore, it is interesting and important question to ask whether NMR rates contain any characteristic information on topological superconductivity. Specifically, the coherence effect is notable. The NMR rate in the presence of a spin-singlet swave superconducting state is enhanced just below a critical temperature T c , owing to the coherence factor [23]. This coherence peak (Hebel-Slichter peak) [24,25] comes from the formation of superconducting gaps. The absence of the peak and a power-law behavior of T −1 1 at low temperatures indicate the occurrence of unconventional states [26][27][28].In this paper we claim that the bulk measurements of NMR rates detect a 3D odd-parity fully-gapped topological superconducting state in time-reversal-invariant multi-orbital systems. An inverse coherence effect just below T c is the signature of this odd-parity state; the coherence factor contributes to the NMR rates with an opposite sign to that of the conventional s-wave states. Our self-consistent calculations in the model of Cu x Bi 2 Se 3 [13] show that this sign reversal leads to an anti-peak behavior of the NMR rates below T c . Using the Fermion anticommutation property, we show that the odd parity allows a twist of a gap fun...

show abstract

mentioning

confidence: 99%

“…Finally, we discuss the NMR rate with anisotropic oddparity states labeled by E u : 16,19,30]. According to Ref.…”

mentioning

confidence: 99%

Inverse coherence effects in nuclear magnetic relaxation rates as a sign of topological superconductivity

2015

View full text Add to dashboard Cite

show abstract

“…113,114) A representative candidate for time-reversal symmetric topological superconductors in class DIII in three dimensions is Cu x Bi 2 Se 3 , which is a carrier-doped topological insulator, and is expected to realize an odd-parity pairing state. [115][116][117][118][119][120][121][122][123][124][125][126][127][128][129][130][131] Since there are already several excellent reviews on these materials, 113, 114, 132, 133) we will not discuss them here. Instead, we discuss some other possible candidate materials in this section.…”

Section: Candidate Materialsmentioning

confidence: 99%

Majorana Fermions and Topology in Superconductors

2016

View full text Add to dashboard Cite

type of quantum statistics referred to as non-Abelian statistics, which is distinct from bose and fermi statistics, and can be utilized for application to topological quantum computation. Also, Majorana fermions give rise to various exotic phenomena such as "fractionalization", nonlocal correlation, and "teleportation". A pedagogical review of these subjects is presented.We also discuss interaction effects on topological classification of superconductors, and the basic properties of Weyl superconductors.

show abstract

“…For a simplified model with spheroidal Fermi surface, this SC pairing is known to be equivalent to the A phase of 3 He and has two bulk nodes [23,24]. However, by including in the model the terms responsible for hexagonal warping of the Fermi surface, this SC was argued to have a full pairing gap [22]. If confirmed, this could be the first three-dimensional topological superconductor with a fully-gapped bulk ever discovered.…”

Section: Introductionmentioning

confidence: 99%

“…The alluded pairing, with a salient in-plane anisotropy, has also been called a nematic SC [22]. For a simplified model with spheroidal Fermi surface, this SC pairing is known to be equivalent to the A phase of 3 He and has two bulk nodes [23,24].…”

Section: Introductionmentioning

confidence: 99%

Nematic superconductivity in CuxBi2Se3 : Surface Andreev bound states

Hao

Ting

2017

Phys. Rev. B

View full text Add to dashboard Cite

We study theoretically the topological surface states (TSSs) and the possible surface Andreev bound states (SABSs) of CuxBi2Se3 which is known to be a topological insulator at x = 0. The superconductivity (SC) pairing of this compound is assumed to have the broken spin-rotation symmetry, similar to that of the A-phase of 3 He as suggested by recent nuclear-magnetic resonance experiments. For both spheroidal and corrugated cylindrical Fermi surfaces with the hexagonal warping terms, we show that the bulk SC gap is rather anisotropic; the minimum of the gap is negligibly small as comparing to the maximum of the gap. This would make the fully-gapped pairing effectively nodal. For a clean system, our results indicate the bulk of this compound to be a topological superconductor with the SABSs appearing inside the bulk SC gap. The zero-energy SABSs which are Majorana fermions, together with the TSSs not gapped by the pairing, produce a zero-energy peak in the surface density of states (SDOS). The SABSs are expected to be stable against short-range nonmagnetic impurities, and the local SDOS is calculated around a nonmagnetic impurity. The relevance of our results to experiments is discussed.

show abstract

Quantum quenches and competing orders

Cited by 90 publications

References 16 publications

Inverse coherence effects in nuclear magnetic relaxation rates as a sign of topological superconductivity

Inverse coherence effects in nuclear magnetic relaxation rates as a sign of topological superconductivity

Majorana Fermions and Topology in Superconductors

Nematic superconductivity in CuxBi2Se3 : Surface Andreev bound states

Contact Info

Product

Resources

About