Quantum oscillations of the nonequilibrium chemical potential in Josephson junctions

We investigate a chiral d-density wave (CDDW) mean field model Hamiltonian in the momentum space suitable for the hole-doped cuprates, such as YBCO, in the pseudogap phase to obtain the Fermi surface (FS) topologies, including the anisotropy parameter() and the elastic scattering by disorder potential (). For , with the chemical potential eV for 10% doping level and (where eV is the first neighbor hopping), at zero/non-zero magnetic field (), the FS on the first Brillouin zone is found to correspond to electron pockets around antinodal regions and barely visible patches around nodal regions. For , we find Pomeranchuk distortion of FS. We next relate our findings regarding FS to the magneto-quantum oscillations in the electronic specific heat. Since the nodal quasiparticle energy values for are found to be greater than for , the origin of the oscillations for nonzero corresponds to the Fermi pockets around antinodal regions. The oscillations are shown to take place in the weak disorder regime (eV) only.

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Hidden quasi-symmetries stabilize non-trivial quantum oscillations in CoSi

10.21203/rs.3.rs-811950/v1 ◽

2021 ◽

Author(s):

Chunyu Guo ◽

Lunhui Hu ◽

Carsten Putzke ◽

Jonas Diaz ◽

Xiangwei Huang ◽

...

Keyword(s):

Chemical Potential ◽

Topological Defects ◽

Fine Tuning ◽

Quantum Oscillations ◽

Von Neumann ◽

Classification Framework ◽

Isolated Points ◽

Exact Symmetry ◽

Symmetric Points ◽

Crystalline Symmetry

Abstract Unlocking the exotic properties promised to occur in topologically non-trivial semi-metals currently requires significant fine-tuning. Crystalline symmetry restricts the location of topological defects to isolated points (0D) or lines (1D), as formalized by the Wigner-Von Neumann theorem. The scarcity of materials in which these anomalies occur at the chemical potential is a major obstacle towards their applications. Here we show how non-crystalline quasi-symmetries stabilize near-degeneracies of bands over extended regions in energy and in the Brillouin zone. Specifically, a quasi-symmetry is an exact symmetry of a k∙p Hamiltonian to lower-order that is broken by higher-order terms. Hence quasi-symmetric points are gapped, yet the gap is parametrically small and therefore does not influence the physical properties of the system. We demonstrate that in the eV-bandwidth semi-metal CoSi an internal quasi-symmetry stabilizes gaps in the 1-2 meV range over a large near-degenerate plane (2D). This quasi-symmetry is key to explaining the surprising simplicity of the experimentally observed quantum oscillations of four interpenetrating Fermi surfaces around the R-point. Untethered from the limitations of crystalline symmetry, quasi-symmetries eliminate the need for fine-tuning as they enforce sources of large Berry curvature to occur at the chemical potential, and thereby lead to new Wigner-Von Neumann classifications of solids. Quasi-symmetries arise from a comparable splitting of degenerate states by spin-orbit coupling and by orbital dispersion - suggesting a hidden classification framework for symmetry groups and materials in which quasi-symmetries are critical to understand the low-energy physics.

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Chemical potential asymmetry and quantum oscillations in insulators

Physical Review B ◽

10.1103/physrevb.94.125140 ◽

2016 ◽

Vol 94 (12) ◽

Cited By ~ 25

Author(s):

Hridis K. Pal ◽

Frédéric Piéchon ◽

Jean-Noël Fuchs ◽

Mark Goerbig ◽

Gilles Montambaux

Keyword(s):

Chemical Potential ◽

Quantum Oscillations

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Correlation-Induced Band Competition in SrTiO3/LaAlO3

MRS Advances ◽

10.1557/adv.2017.92 ◽

2017 ◽

Vol 2 (23) ◽

pp. 1243-1248 ◽

Cited By ~ 4

Author(s):

Eran Maniv ◽

Yoram Dagan ◽

Moshe Goldstein

Keyword(s):

Critical Temperature ◽

Carrier Density ◽

Chemical Potential ◽

Total Density ◽

Continuous Control ◽

Oxide Interface ◽

Electronic Interactions ◽

Quantum Oscillations ◽

Band Competition ◽

Nonmonotonic Behavior

ABSTRACTThe oxide interface SrTiO3/LaAlO3 supports a 2D electron liquid displaying superconductivity and magnetism, while allowing for a continuous control of the electron density using a gate. Our recent measurements have shown a similar surprising nonmonotonic behavior as function of the gate voltage (carrier density) of three quantities: the superconducting critical temperature and field, the inverse Hall coefficient, and the frequency of quantum oscillations. While the total density has to be monotonic as function of gate, the last result indicates that one of the involved bands has a nonmontonic occupancy as function of the chemical potential. We show how electronic interactions can lead to such an effect, by creating a competition between the involved bands and making their sturcture non-rigid, and thus account for all these effects. Adding Fock terms to our previous Hartree treatment makes this scenario even more generic.

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Angle-Dependent Quantum-Oscillations due to Chemical Potential Oscillation in Quasi-Two-Dimensional Multiband Fermi Liquids

Journal of the Physical Society of Japan ◽

10.1143/jpsj.68.1801 ◽

1999 ◽

Vol 68 (6) ◽

pp. 1801-1804 ◽

Cited By ~ 13

Author(s):

Masahiro Nakano

Keyword(s):

Chemical Potential ◽

Fermi Liquids ◽

Two Dimensional ◽

Potential Oscillation ◽

Quantum Oscillations

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Shadow surface states in topological Kondo insulators

New Journal of Physics ◽

10.1088/1367-2630/ac4124 ◽

2021 ◽

Author(s):

Areg Ghazaryan ◽

Emilian Nica ◽

Onur Erten ◽

Pouyan Ghaemi

Keyword(s):

High Frequency ◽

Dirac Point ◽

Chemical Potential ◽

Surface States ◽

Support Surface ◽

Finite Frequency ◽

Fermi Surfaces ◽

Quantum Oscillations ◽

Kondo Insulators ◽

Out Of Plane

Abstract The surface states of 3D topological insulators in general have negligible quantum oscillations when the chemical potential is tuned to the Dirac points. In contrast, we find that topological Kondo insulators can support surface states with an arbitrarily large Fermi surfaces when the chemical potential is pinned to the Dirac point. We illustrate that these Fermi surfaces give rise to finite-frequency quantum oscillations, which can become comparable to the extremal area of the unhybridized bulk bands. We show that this occurs when the crystal symmetry is lowered from cubic to tetragonal in a minimal two-orbital model. We label such surface modes as `shadow surface states'. Moreover, we show that the sufficient NNN out-of-plane hybridization leading to shadow surface states can be self-consistently stabilized for tetragonal topological Kondo insulators. Consequently, shadow surface states provide an important example of high-frequency quantum oscillations beyond the context of cubic topological Kondo insulators.

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