Fermi surface reconstruction by a charge density wave with finite correlation length

AbstractThe Kagome superconductors AV3Sb5 (A = K, Rb, Cs) have received enormous attention due to their nontrivial topological electronic structure, anomalous physical properties and superconductivity. Unconventional charge density wave (CDW) has been detected in AV3Sb5. High-precision electronic structure determination is essential to understand its origin. Here we unveil electronic nature of the CDW phase in our high-resolution angle-resolved photoemission measurements on KV3Sb5. We have observed CDW-induced Fermi surface reconstruction and the associated band folding. The CDW-induced band splitting and the associated gap opening have been revealed at the boundary of the pristine and reconstructed Brillouin zones. The Fermi surface- and momentum-dependent CDW gap is measured and the strongly anisotropic CDW gap is observed for all the V-derived Fermi surface. In particular, we have observed signatures of the electron-phonon coupling in KV3Sb5. These results provide key insights in understanding the nature of the CDW state and its interplay with superconductivity in AV3Sb5 superconductors.

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Holographic Fermi surfaces in charge density wave from D2-D8

Journal of High Energy Physics ◽

10.1007/jhep09(2021)160 ◽

2021 ◽

Vol 2021 (9) ◽

Author(s):

Subir Mukhopadhyay ◽

Nishal Rai

Keyword(s):

Dirac Equation ◽

Fermi Surface ◽

Spectral Density ◽

Charge Density ◽

Charge Density Wave ◽

Density Wave ◽

Spin Density Wave ◽

Fermi Surfaces ◽

A Charge ◽

Ionic Lattice

Abstract D2-D8 model admits a numerical solution that corresponds to a charge density wave and a spin density wave. Considering that as the background, we numerically solve the Dirac equation for probe fermions. From the solution, we obtain the Green’s function and study the behaviour of the spectral density. We begin with generic fermions and have studied the formation of the Fermi surface and where it develops a gap. In addition, we have incorporated an ionic lattice and study its effect on the Fermi surface. Then we analysed the worldvolume fermions. In this particular model we do not find Fermi surface for the dual operators.

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Atomic-scale strain manipulation of a charge density wave

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1718931115 ◽

2018 ◽

Vol 115 (27) ◽

pp. 6986-6990 ◽

Cited By ~ 12

Author(s):

Shang Gao ◽

Felix Flicker ◽

Raman Sankar ◽

He Zhao ◽

Zheng Ren ◽

...

Keyword(s):

Fermi Surface ◽

Charge Density ◽

Charge Density Wave ◽

Density Wave ◽

Atomic Scale ◽

Scanning Tunneling ◽

Electronic Band ◽

Simple Method ◽

Wide Range ◽

A Charge

A charge density wave (CDW) is one of the fundamental instabilities of the Fermi surface occurring in a wide range of quantum materials. In dimensions higher than one, where Fermi surface nesting can play only a limited role, the selection of the particular wavevector and geometry of an emerging CDW should in principle be susceptible to controllable manipulation. In this work, we implement a simple method for straining materials compatible with low-temperature scanning tunneling microscopy/spectroscopy (STM/S), and use it to strain-engineer CDWs in 2H-NbSe2. Our STM/S measurements, combined with theory, reveal how small strain-induced changes in the electronic band structure and phonon dispersion lead to dramatic changes in the CDW ordering wavevector and geometry. Our work unveils the microscopic mechanism of a CDW formation in this system, and can serve as a general tool compatible with a range of spectroscopic techniques to engineer electronic states in any material where local strain or lattice symmetry breaking plays a role.

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