Figure 1

(a) Definitions of the $p$ and $s$ ARPES configurations, along with the various angles used in the calculations. (b) and (c) illustrate, respectively, the even and odd combination of the $d_{xz}$ and $d_{yz}$ orbitals, along with the definition of the ${\theta }_{FS}$ angle.Reuse & Permissions

Figure 2

(a)–(e) Angular dependence of the $x$ (in red), $y$ (in green), and $z$ (in blue) components of the photoemission matrix elements related to the various 3$d$ orbitals (see the text). (f)–(j) Same as (a)–(e) but using the simplified matrix elements (see the text). We used $h\nu =21.2$ eV and $k_F=0.3\pi$.Reuse & Permissions

Figure 3

Fermi surface intensity patterns of Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$. (a)–(d) Experimental results with different photon energies, polarizations, and incident beam directions. (e)–(h) Corresponding simulated results using the simplified model described in the text (simulation A: optimized orbital configuration). The inner $\Gamma$-centered $\alpha$ and ${\alpha }^{\prime }$ Fermi surface pockets with $d_e$ and $d_o$ orbital characters are considered degenerate. The outer one ($\beta$ band) is associated with the $d_{xy}$ orbital. The tip of the M-centered Fermi surface pockets has pure $d_{xz}$ or $d_{yz}$ orbital characters while the inner part carries a dominant $d_{xy}$ orbital character. (i)–(l) Same as (e)–(h) but using a wrong orbital assignment (simulation B). The orbital characters of the $\beta$ and ${\alpha }^{\prime }$ bands have been exchanged compared to simulation A. The orbital characters of the tip and inner part of the M-centered FS have also been exchanged. Red double arrows and blue arrows indicate the in-plane components of the orientation of the light polarization and direction, respectively.Reuse & Permissions

Figure 4

First row: ARPES intensity plots of Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ recorded along the M-$\Gamma$ direction using 138 eV photons and (a) $\sigma$, (b) $\pi$, and (c) circular right polarizations. Second row: Corresponding 1D curvature intensity plots (Ref. 33) along the momentum direction. Third row: Corresponding MDC profile integrated within 10 meV below $E_F$, compared to profiles simulated using the same half-width at half maximum for each band. (j) Direct comparison of the MDC profiles recorded with $\sigma$ (red) and $\pi$ (blue) polarizations.Reuse & Permissions

Figure 5

(a) and (b) give the ARPES intensity in the $p$ configuration with $C_{+}$ and $C_{-}$ polarizations, respectively. (c) MDC profiles near $E_F$ corresponding to (a) and (b). (d) and (e) Simulated ARPES intensity in the $p$ configuration with $C_{+}$ and $C_{-}$ polarizations, respectively. (f) MDC profiles near $E_F$ corresponding to (d) and (e). (g) and (h) show the ARPES intensity in the $s$ configuration with $C_{+}$ and $C_{-}$ polarizations, respectively. (i) MDC profiles near $E_F$ corresponding to (g) and (h). (j) and (k) Simulated ARPES intensity in the $s$ configuration with $C_{+}$ and $C_{-}$ polarizations, respectively. (l) MDC profiles near $E_F$ corresponding to (j) and (k). To simplify the simulations, we chose $\gamma =\pi /4$.Reuse & Permissions

Figure 6

(a)–(c) Fermi surface intensity patterns of Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ recorded with 60 eV circular polarized light. The white arrows show the direction of the incoming light. (d)–(f) Corresponding simulation results.Reuse & Permissions

Figure 7

(a)–(e) ARPES intensity plots of Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ recorded around the $\Gamma$ point with $C_{+}$ polarized light. (f) Normalized intensity difference between the left and right sides of panels (a)–(e). The photon energy has been converted into $k_z$ using an inner potential $V_0=14.5$ eV.[28] (g) Photoemission intensity plot of the electronic dispersion of Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ as a function of $k_z$. The data have been recorded between 30 and 90 eV using $C_{+}$ light. (h)–(j) Simulations corresponding to the experimental conditions in (g). The phase ${\gamma }_{\delta }$ of Eq. (14) has been fixed to $k_{z}c+\delta$.Reuse & Permissions

Figure 8

Fermi surface and band structure of FeTe${}_{0.55}$Se${}_{0.45}$. (a)–(b) Fermi surface intensity plots recorded with unpolarized photons (21.2 eV) directed along $\Gamma$-M and $\Gamma$-X, respectively. (c)–(d) Corresponding simulations for the $d_o$ band, with the light momentum indicated by the white arrows. (e) ARPES intensity cut recorded along the blue line in (a). (f) Simulations of the intensity cut in (e).Reuse & Permissions

Figure 9

Schematic distribution of the orbital characters in Ba${}_{0.6}$K${}_{0.4}$Fe${}_2$As${}_2$ and FeTe${}_{0.55}$Se${}_{0.45}$. Red: $d_{xz}$; Blue: $d_{yz}$; Green: $d_{xy}$.Reuse & Permissions