Magnetic dilution effect and topological phase transitions in (Mn1-xPbx)Bi2Te4
[1];
[3];
[3];
- University of California, Los Angeles, CA (United States)
- National Cheng Kung University, Tainan (Taiwan)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- George Mason University, Fairfax, VA (United States)
- National Cheng Kung University, Tainan (Taiwan); Center for Quantum Frontiers of Research and Technology (QFort), Tainan (Taiwan); National Center for Theoretical Sciences, Taipei (Taiwan)
We report, as the first intrinsic antiferromagnetic topological insulator, MnBi2Te4 has provided a material platform to realize various emergent phenomena arising from the interplay of magnetism and band topology. Here, by investigating (Mn1-xPbx)Bi2Te4(0 ≤ x ≤ 0.82) single crystals via the x-ray, electrical transport, magnetometry and neutron measurements, chemical analysis, external pressure, and first-principles calculations, we reveal the magnetic dilution effect on the magnetism and band topology in MnBi2Te4. With increasing x, both lattice parameters a and c expand linearly by around 2%. All samples undergo the paramagnetic to A-type antiferromagnetic transition with the Néel temperature decreasing lineally from 24 K at x = 0 to 2 K at x = 0.82. Our neutron data refinement of the x = 0.37 sample indicates that the ordered moment is 4.3(1)μB/Mn at 4.85 K and the amount of the MnBi antisites is negligible within the error bars. Isothermal magnetization data reveal a slight decrease of the interlayer plane-plane antiferromagnetic exchange interaction and a monotonic decrease of the magnetic anisotropy due to diluting magnetic ions and enlarging the unit cell. For x = 0.37, the application of external pressures enhances the interlayer antiferromagnetic coupling, boosting the Néel temperature at a rate of 1.4 K/GPa and the saturation field at a rate of 1.8 T/GPa. Furthermore, our first-principles calculations reveal that the band inversion in the two end materials, MnBi2Te4 and PbBi2Te4, occurs at the Γ and Z point, respectively, while two gapless points appear at x = 0.44 and x = 0.66, suggesting possible topological phase transitions with doping.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES); Ministry of Science and Technology (MOST)
- Grant/Contract Number:
- AC05-00OR22725; SC0021117; SC0021089; MOST110-2636-M-006-016; MOST107-2627-E-006-001
- OSTI ID:
- 1883748
- Alternate ID(s):
- OSTI ID: 1885860
- Journal Information:
- Physical Review. B, Vol. 106, Issue 4; ISSN 2469-9950
- Publisher:
- American Physical Society (APS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
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