P06S

23BG012

BL-9A

Probing the Electronic Band Structure of Altermagnetic
MnTe: An ARPES Study
Kazi Golam Martuzaa, Yogendra Kumara, Shiv Kumarb,c, Shin-ichiro Idetaa,b andKenya Shimadaa,ba

Graduate School of Advanced Science and Engineering, Hiroshima University, Japan 739-0046b
Hiroshima Synchrotron Radiation Centre (HiSOR), Hiroshima University, Japan 739-0046
cInstitute of Microelectronics, Agency for Science, Technology and Research (A*STAR), Singapore
Keywords: MnTe, altermagnet, electronic structure, ARPES

Altermagnetism is a recently recognized type of magnetism with vanishing net magnetization and atime-reversal symmetry broken electronic structure and have attracted much interest for their distinct
magnetic characteristics and prospective applications [1]. As a canonical altermagnetic material, MnTe hasgarnered a lot of interest recently [2-6]. MnTe with a hexagonal NiAs-type structure is one of the few
semiconductors among the 3d transition-metal compounds [3,4].
In this study, we investigated the electronic band structure of the hexagonal MnTe (0001) bulk single
crystal using polarization dependent angle-resolved photoemission spectroscopy (ARPES). The samples
were prepared by mixing stoichiometric amounts of finely powdered Mn and Te and sealed in evacuatedquartz ampoule at 10-5 pa. We grew MnTe single crystal by solid reaction method and cut it to exhibit the(0001) plane. For getting clean surface we sputtered and annealed the sample. We used 2kV beam energy
for sputtering and annealing temperature was 330 degree Celsius. By repeated cycles of sputtering andannealing, we could finally get a clean surface. The impurity of the surface was checked by the Augerelectron spectroscopy and the long-range order was confirmed by the sharp hexagonal low-energy electron
diffraction (LEED) spots. The polarization dependent ARPES experiments were done on HiSOR BL-9A
equipped with an ASTRAIOS electron analyzer. We set the photon energy at 40 eV and the temperature at
200K. The polarization direction of the incident light was controlled by the undulator magnets configuration.
Figs. 1(a) and 1(b) show the kx-ky ARPES intensity map at the chemical potential taken with the sand p-polarization geometries, respectively. Although MnTe is a semiconductor, due to the intrinsic hole
doping, the chemical potential is located below the top of the valence band. The photoemission intensity ismuch intense taken at the s-polarization geometry indicating that the electron wave functions are odd withrespect to the mirror plane. It indicates the observed valence bands are derived from Mn 3𝑑𝑥𝑦 , Mn 3𝑑𝑦𝑧 ,and Te 5𝑝𝑦 states. The spectral intensity is strong around the Γ̅ point and the ARPES intensity map along̅̅̅̅ direction in Fig. 1(c) suggests an existence of hole-like bands, which is consistent with the bandthe ΓKstructure calculations [5,7]. The ARPES intensity mapping at the chemical potential in Fig. 1(a) is compatible
with the hexagonal (0001) surface.
̅K(a)

(b)

̅



̅
K(c)

̅K

̅




̅
K(d)

FIGURE 1. High-resolution ARPES results on MnTe (0001) single crystal taken at 200K and h=40 eV. kx-ky mapping at the chemical potential with the s-polarization (a) and p-polarization (b) geometries. ARPES
̅̅̅̅ high symmetry line with the s-polarization (c) and p-polarization (d) geometries.
intensity map along the ΓK

REFERENCES[1] S. Lee et al., Phys. Rev. Lett. 132, 036702 (2024).
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[4] H. Sato et al., Journal of Magnetism and Magnetic Materials 140-144, 153-154 (1995).
[5] P. E. Faria Junior et al, Phys. Rev. B 107, L100417 (2023).
[6] T. Osumi et al., http://arxiv.org/abs/2308.10117.
[7] S. J. Youn et al., Physica Status Solidi (B) 241, 1411–1414 (2004).