X-ray diffraction analysis of the Sb single crystals. The XRD pattern was obtained by using 

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... floating zone method. High-quality Sb single crystal with a length of 5 cm is obtained (Fig. 1, upper-left inset). Small plate-like samples with a typical size of 2 × 3 × 0 . 1 mm 3 can be obtained from these large pieces. The crystal structure and the quality of the obtained Sb crystals were characterized by the X-ray diffraction (XRD) (Fig. 1). Sb has an A7 crystal structure with a rhombohedral unit cell that contains two Sb atoms (upper-right inset in Fig. 1)[7]. The rhombohedral structure can be thought of as a simple cubic structure stretched along its diagonal axis; this axis then becomes the trigonal (111) axis and retains three-fold symmetry [13, 14]. This trigonal axis of the Sb crystal structure corresponds to the (003) direction in the hexagonal crystallographic structure [14, 15] and the (111) direction in the rhombohedral crystallographic structure [13, 14]. As seen in Fig. 1, all the diffraction peaks of the cleaved Sb single crystal can be indexed into (0 , 0 , h ) in the hexagonal crystallographic structure, with h being 3, 6 and 9. The c-axis lattice constant is determined to be c = 11 . 223 Awhich is consistent with the result reported before [6, 7]. The sample cleavage plane is then (003)Hex/(111)Rhom, denoted as Sb(111) hereafter. The angle-resolved photoemission measurements were performed on our newly developed VUV laser-based spin- and angle-resolved photoemission system (SARPES) [5, 16], which combines the Scienta R4000 analyzer with Mott-type spin detectors. The photon energy of the laser is 6.994 eV with a bandwidth of 0.26 meV. The best energy resolution for regular ARPES measurements is ∼ 1 meV. The angular resolution is ∼ 0.3 ◦ , corresponding to a momentum resolution 0.004 A − 1 for the 6.994 eV photon energy. The single crystal Sb samples were cleaved and in situ measured in an ultra-high vacuum with a base pressure better than 5 × 10 − 11 Torr. Figure 2 shows the Fermi surface mapping of Sb(111). In the mapping covering a large momentum space (Fig. 2a), there is a small Fermi pocket around Γ point, and six lobes of Fermi pockets surrounding the central Fermi pocket. Near M, there is the third oval-shaped Fermi pocket. The band structure measurements along high symmetry cuts (Figs. 2c and 2d) indicate that the central Fermi pocket is electron-like while the six lobes are hole-like. Fig. 2b shows a high resolution measurements of the central electron-like Fermi pocket that shows a clear hexagon-like shape. It is noted that, while the electron-like Fermi pocket near Γ shows nearly a six-fold symmetry, the spectral weight distribution of the six hole-like lobes has an obvious three-fold symmetry (Fig. 2a). It is known that the bulk Sb has three-fold symmetry and the Sb(111) surface has six-fold symmetry. Therefore, the central ...

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... floating zone method. High-quality Sb single crystal with a length of 5 cm is obtained (Fig. 1, upper-left inset). Small plate-like samples with a typical size of 2 × 3 × 0 . 1 mm 3 can be obtained from these large pieces. The crystal structure and the quality of the obtained Sb crystals were characterized by the X-ray diffraction (XRD) (Fig. 1). Sb has an A7 crystal structure with a rhombohedral unit cell that contains two Sb atoms (upper-right inset in Fig. 1)[7]. The rhombohedral structure can be thought of as a simple cubic structure stretched along its diagonal axis; this axis then becomes the trigonal (111) axis and retains three-fold symmetry [13, 14]. This trigonal axis of the Sb crystal structure corresponds to the (003) direction in the hexagonal crystallographic structure [14, 15] and the (111) direction in the rhombohedral crystallographic structure [13, 14]. As seen in Fig. 1, all the diffraction peaks of the cleaved Sb single crystal can be indexed into (0 , 0 , h ) in the hexagonal crystallographic structure, with h being 3, 6 and 9. The c-axis lattice constant is determined to be c = 11 . 223 Awhich is consistent with the result reported before [6, 7]. The sample cleavage plane is then (003)Hex/(111)Rhom, denoted as Sb(111) hereafter. The angle-resolved photoemission measurements were performed on our newly developed VUV laser-based spin- and angle-resolved photoemission system (SARPES) [5, 16], which combines the Scienta R4000 analyzer with Mott-type spin detectors. The photon energy of the laser is 6.994 eV with a bandwidth of 0.26 meV. The best energy resolution for regular ARPES measurements is ∼ 1 meV. The angular resolution is ∼ 0.3 ◦ , corresponding to a momentum resolution 0.004 A − 1 for the 6.994 eV photon energy. The single crystal Sb samples were cleaved and in situ measured in an ultra-high vacuum with a base pressure better than 5 × 10 − 11 Torr. Figure 2 shows the Fermi surface mapping of Sb(111). In the mapping covering a large momentum space (Fig. 2a), there is a small Fermi pocket around Γ point, and six lobes of Fermi pockets surrounding the central Fermi pocket. Near M, there is the third oval-shaped Fermi pocket. The band structure measurements along high symmetry cuts (Figs. 2c and 2d) indicate that the central Fermi pocket is electron-like while the six lobes are hole-like. Fig. 2b shows a high resolution measurements of the central electron-like Fermi pocket that shows a clear hexagon-like shape. It is noted that, while the electron-like Fermi pocket near Γ shows nearly a six-fold symmetry, the spectral weight distribution of the six hole-like lobes has an obvious three-fold symmetry (Fig. 2a). It is known that the bulk Sb has three-fold symmetry and the Sb(111) surface has six-fold symmetry. Therefore, the central ...

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... floating zone method. High-quality Sb single crystal with a length of 5 cm is obtained (Fig. 1, upper-left inset). Small plate-like samples with a typical size of 2 × 3 × 0 . 1 mm 3 can be obtained from these large pieces. The crystal structure and the quality of the obtained Sb crystals were characterized by the X-ray diffraction (XRD) (Fig. 1). Sb has an A7 crystal structure with a rhombohedral unit cell that contains two Sb atoms (upper-right inset in Fig. 1)[7]. The rhombohedral structure can be thought of as a simple cubic structure stretched along its diagonal axis; this axis then becomes the trigonal (111) axis and retains three-fold symmetry [13, 14]. This trigonal axis of the Sb crystal structure corresponds to the (003) direction in the hexagonal crystallographic structure [14, 15] and the (111) direction in the rhombohedral crystallographic structure [13, 14]. As seen in Fig. 1, all the diffraction peaks of the cleaved Sb single crystal can be indexed into (0 , 0 , h ) in the hexagonal crystallographic structure, with h being 3, 6 and 9. The c-axis lattice constant is determined to be c = 11 . 223 Awhich is consistent with the result reported before [6, 7]. The sample cleavage plane is then (003)Hex/(111)Rhom, denoted as Sb(111) hereafter. The angle-resolved photoemission measurements were performed on our newly developed VUV laser-based spin- and angle-resolved photoemission system (SARPES) [5, 16], which combines the Scienta R4000 analyzer with Mott-type spin detectors. The photon energy of the laser is 6.994 eV with a bandwidth of 0.26 meV. The best energy resolution for regular ARPES measurements is ∼ 1 meV. The angular resolution is ∼ 0.3 ◦ , corresponding to a momentum resolution 0.004 A − 1 for the 6.994 eV photon energy. The single crystal Sb samples were cleaved and in situ measured in an ultra-high vacuum with a base pressure better than 5 × 10 − 11 Torr. Figure 2 shows the Fermi surface mapping of Sb(111). In the mapping covering a large momentum space (Fig. 2a), there is a small Fermi pocket around Γ point, and six lobes of Fermi pockets surrounding the central Fermi pocket. Near M, there is the third oval-shaped Fermi pocket. The band structure measurements along high symmetry cuts (Figs. 2c and 2d) indicate that the central Fermi pocket is electron-like while the six lobes are hole-like. Fig. 2b shows a high resolution measurements of the central electron-like Fermi pocket that shows a clear hexagon-like shape. It is noted that, while the electron-like Fermi pocket near Γ shows nearly a six-fold symmetry, the spectral weight distribution of the six hole-like lobes has an obvious three-fold symmetry (Fig. 2a). It is known that the bulk Sb has three-fold symmetry and the Sb(111) surface has six-fold symmetry. Therefore, the central ...

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... floating zone method. High-quality Sb single crystal with a length of 5 cm is obtained (Fig. 1, upper-left inset). Small plate-like samples with a typical size of 2 × 3 × 0 . 1 mm 3 can be obtained from these large pieces. The crystal structure and the quality of the obtained Sb crystals were characterized by the X-ray diffraction (XRD) (Fig. 1). Sb has an A7 crystal structure with a rhombohedral unit cell that contains two Sb atoms (upper-right inset in Fig. 1)[7]. The rhombohedral structure can be thought of as a simple cubic structure stretched along its diagonal axis; this axis then becomes the trigonal (111) axis and retains three-fold symmetry [13, 14]. This trigonal axis of the Sb crystal structure corresponds to the (003) direction in the hexagonal crystallographic structure [14, 15] and the (111) direction in the rhombohedral crystallographic structure [13, 14]. As seen in Fig. 1, all the diffraction peaks of the cleaved Sb single crystal can be indexed into (0 , 0 , h ) in the hexagonal crystallographic structure, with h being 3, 6 and 9. The c-axis lattice constant is determined to be c = 11 . 223 Awhich is consistent with the result reported before [6, 7]. The sample cleavage plane is then (003)Hex/(111)Rhom, denoted as Sb(111) hereafter. The angle-resolved photoemission measurements were performed on our newly developed VUV laser-based spin- and angle-resolved photoemission system (SARPES) [5, 16], which combines the Scienta R4000 analyzer with Mott-type spin detectors. The photon energy of the laser is 6.994 eV with a bandwidth of 0.26 meV. The best energy resolution for regular ARPES measurements is ∼ 1 meV. The angular resolution is ∼ 0.3 ◦ , corresponding to a momentum resolution 0.004 A − 1 for the 6.994 eV photon energy. The single crystal Sb samples were cleaved and in situ measured in an ultra-high vacuum with a base pressure better than 5 × 10 − 11 Torr. Figure 2 shows the Fermi surface mapping of Sb(111). In the mapping covering a large momentum space (Fig. 2a), there is a small Fermi pocket around Γ point, and six lobes of Fermi pockets surrounding the central Fermi pocket. Near M, there is the third oval-shaped Fermi pocket. The band structure measurements along high symmetry cuts (Figs. 2c and 2d) indicate that the central Fermi pocket is electron-like while the six lobes are hole-like. Fig. 2b shows a high resolution measurements of the central electron-like Fermi pocket that shows a clear hexagon-like shape. It is noted that, while the electron-like Fermi pocket near Γ shows nearly a six-fold symmetry, the spectral weight distribution of the six hole-like lobes has an obvious three-fold symmetry (Fig. 2a). It is known that the bulk Sb has three-fold symmetry and the Sb(111) surface has six-fold symmetry. Therefore, the central ...