TY  - JOUR
PB  - SciPost Foundation
DO  - 10.21468/SciPostPhys.18.6.191
TI  - The asymmetric Fermi surface of Bi2201
PY  - 2025/06/17
UR  - https://scipost.org/SciPostPhys.18.6.191
JF  - SciPost Physics
JA  - SciPost Phys.
VL  - 18
IS  - 6
SP  - 191
A1  - Smit, Steef
AU  - Shirkoohi, Kourosh Lwydd
AU  - Mukherjee, Saumya
AU  - Pierantoni, Sergio Barquero
AU  - Bawden, Lewis
AU  - van Heumen, Erik
AU  - Tchiomo, Arnaud Pastel Nono
AU  - Henke, Jans
AU  - van Wezel, Jasper
AU  - Huang, Yingkai
AU  - Kondo, Takeshi
AU  - Takeuchi, Tsunehiro
AU  - Kim, Timur
AU  - Cacho, Cephise
AU  - Zonno, Marta
AU  - Gorovikov, Sergey
AU  - Dugdale, Stephen Brian
AU  - Facio, Jorge I.
AU  - Roslova, Mariia
AU  - Folkers, Laura
AU  - Isaeva, Anna
AU  - Hussey, Nigel
AU  - Golden, Mark
AB  - High-resolution angle-resolved photoemission spectroscopy (ARPES) performed on the single-layered cuprate (Pb$_{1-y}$,Bi$_y$)$_2$Sr$_{2-x}$La$_x$CuO$_{6+\delta}$ (Bi2201) reveals a 6-10% difference in the nodal $k_F$ vectors along the $\Gamma$Y and $\Gamma$X directions. This asymmetry is notably larger than the 2% orthorhombic distortion in the CuO$_2$ plane lattice constants determined using X-ray crystallography from the same samples. First principles calculations indicate that crystal-field splitting of the bands lies at the root of the $k_{F}$ asymmetry. Concomitantly, the nodal Fermi velocities for the $\Gamma$Y quadrant exceed those for $\Gamma$X by 4%. Momentum distribution curve widths for the two nodal dispersions are also anisotropic, showing identical energy dependencies, bar a scaling factor of $\sim$ 1.17$± 0.05$ between $\Gamma$Y and $\Gamma$X. Consequently, the imaginary part of the self-energy is found to be 10-20% greater along $\Gamma$Y than $\Gamma$X. These results emphasize the need to account for Fermi surface asymmetry in the analysis of ARPES data on Bi-based cuprate high temperature superconductors such as Bi2201. To illustrate this point, an orthorhombic tight-binding model (with twofold in-plane symmetry) was used to fit ARPES Fermi surface maps spanning all four quadrants of the Brillouin zone, and the ARPES-derived hole-doping (Luttinger count) was extracted. Comparison of the Luttinger count with one assuming four-fold in-plane symmetry strongly suggests the marked spread in previously-reported Fermi surface areas from ARPES on Bi2201 results from the differences in $k_F$ along $\Gamma$Y and $\Gamma$X. Using this analysis, a new, linear relationship emerges between the hole-doping derived from ARPES ($p_{\text{ARPES}}$) and that derived using the Presland ($p_{\text{Presland}}$) relation such that $p_{\text{ARPES}} = p_{\text{Presland}}+0.11$. The implications for this difference between the ARPES- and Presland-derived estimates for $p$ are discussed and possible future directions to elucidate the origin of this discrepancy are presented.
ER  -

@Article{10.21468/SciPostPhys.18.6.191,
	title={{The asymmetric Fermi surface of Bi2201}},
	author={Steef Smit and Kourosh L. Shirkoohi and Saumya Mukherjee and Sergio Barquero Pierantoni and Lewis Bawden and Erik van Heumen and Arnaud P. N. Tchiomo and Jans Henke and Jasper van Wezel and Yingkai Huang and Takeshi Kondo and Tsunehiro Takeuchi and Timur K. Kim and Cephise Cacho and Marta Zonno and Sergey Gorovikov and Stephen B. Dugdale and Jorge I. Facio and Mariia Roslova and Laura Folkers and Anna Isaeva and Nigel E. Hussey and Mark S. Golden},
	journal={SciPost Phys.},
	volume={18},
	pages={191},
	year={2025},
	publisher={SciPost},
	doi={10.21468/SciPostPhys.18.6.191},
	url={https://scipost.org/10.21468/SciPostPhys.18.6.191},
}