Comparative Study of Magnetic Properties of (Mn1−xAxIV)Bi2Te4 AIV = Ge, Pb, Sn

Estyunin, Dmitry A.; Rybkina, Anna A.; Kokh, Konstantin A.; Tereshchenko, Oleg E.; Likholetova, Marina V.; Klimovskikh, Ilya I.; Shikin, Alexander M.

doi:10.3390/magnetochemistry9090210

Cited by 4 publications

(5 citation statements)

References 42 publications

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“…2(a1,b1) for Ge 12%). However, at temperatures above the Néel temperature, the magnitude of the splitting of these states decreases to zero, similar to the findings in 9,14,43 .…”

Section: (B)supporting

confidence: 85%

“…The energy separation between these states in the CB and VB is indicated by horizontal green lines marked as ∆ 2 . According to the literature, at temperatures below the Néel temperature (24.5-25.0 K for MnBi 2 Te 4 9, 10, 14 and 25-26 K for 12% Ge 43 ), the Te p z states (due to magnetic ordering in the system) are energetically split (see Figs. 2(a1,b1) for Ge 12%).…”

Section: (B)mentioning

confidence: 99%

“…The spectra for higher Ge concentrations in Fig. 2 were measured at temperatures above the Néel temperatures corresponding to these concentrations 43 . Therefore, the dispersions shown in Fig.…”

Section: (B)mentioning

confidence: 99%

“…Notably, the observed changes suggest the potential formation of a plateau with a minimum energy gap at the Γ point in the dependence of gap size It is worth noting that the processes of electronic structure changes in the FM phase, as derived from the calculation results, exhibit a series of TPTs and warrant further theoretical and experimental investigation. Of course, the possibility of transition to the FM phase remains through system remagnetization upon application of an external magnetic field, considering that for Mn 1−x Ge x Bi 2 Te 4 with a Ge concentration of approximately 50%, the magnetic field magnitude required for this remagnetization is significantly less than for pure MnBi 2 Te 4 43 .…”

Section: Gapmentioning

confidence: 99%

“…At the same time, for the Mn 1−x [Ge, Sn, Pb] x Bi 2 Te 4 compounds, it was revealed that with an increase in the concentration of non-magnetic atoms, the magnetic properties also change. The Néel temperature decreases from 24.5 K to 10-15 K when Mn atoms are replaced by Ge, Pb, or Sn atoms at concentrations of 50-80%, and further down to 5 K. Additionally, the spin-flop transition threshold is reduced from 7 Tesla to 1-2 Tesla, and further to 0.5 Tesla 43 . This means that, while the remagnetization in MnBi 2 Te 4 and the corresponding transition from the AFM to FM state requires the application of a magnetic field of approximately 7 Tesla, systems with a 50% replacement of the magnetic atom by non-magnetic elements require only 1-1.5 Tesla.…”

Section: Introductionmentioning

confidence: 99%

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Phase transitions, Dirac and WSM states in Mn1−xGexBi2Te4

Shikin,

Zaitsev,

Estyunina

et al. 2024

Preprint

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Using angle-resolved photoemission spectroscopy (ARPES) and density functional theory (DFT), an experimental andtheoretical study of changes in the electronic structure (dispersion dependencies) and corresponding modification of the energyband gap at the Dirac point (DP) for topological insulator (TI) Mn1−xGexBi2Te4 have been carried out with gradual replacementof magnetic Mn atoms by non-magnetic Ge atoms when concentration of the latter was varied from 10% to 75%. It was shownthat when Ge concentration increases then the bulk band gap decreases and reaches zero plateau in the concentration range of45%–60% while non-topological surface states (TSS) are present and exhibit an energy splitting of 100 and 70 meV in differenttypes of measurements. It was also shown that TSS disappear from the measured band dispersions at a Ge concentrationof about 40%. DFT calculations of Mn1−xGexBi2Te4 band structure were carried out to identify the nature of observed banddispersion features and to analyze a possibility of magnetic Weyl semimetal state formation in this system. These calculationswere performed for both antiferromagnetic (AFM) and ferromagnetic (FM) ordering types while the spin-orbit coupling (SOC)strength was varied or a strain (compression or tension) along the c-axis was applied. Calculations show that two differentseries of topological phase transitions (TPTs) may be implemented in this system depending on the magnetic ordering. At AFMordering transition between TI and trivial insulator phase goes through the Dirac semimetal state, whereas for FM phase suchroute admits three intermediate states instead of one (TI — Dirac semimetal — Weyl semimetal — Dirac semimetal — trivialinsulator). Weyl points that form in FM system along the ΓZ direction annihilate when either the SOC strength decreases or asufficient tensile strain is applied, which is accompanied by the corresponding TPTs. Model calculations of local magneticordering influence in AFM Mn1−xGexBi2Te4 was carried out by alternating Mn layers and Ge-doped layers and showed that themagnetic Weyl semimetal state in this system is reachable at a Ge concentration of approximately 40% without application ofany external magnetic fields

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“…2(a1,b1) for Ge 12%). However, at temperatures above the Néel temperature, the magnitude of the splitting of these states decreases to zero, similar to the findings in 9,14,43 .…”

Section: (B)supporting

confidence: 85%

Section: (B)mentioning

confidence: 99%

Section: (B)mentioning

confidence: 99%

Section: Gapmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phase transitions, Dirac and WSM states in Mn1−xGexBi2Te4

Shikin,

Zaitsev,

Estyunina

et al. 2024

Preprint

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The delicate coupling between magnetism and magneto-transport in Fermi-energy-adjusted MnBi2Te4 crystals

Cao,

Lv,

Luo

et al. 2024

Applied Physics Letters

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We explored the coupling between magnetic and magneto-transport properties in MnBi2Te4 crystals with Fermi energy EF ranging from 10 to 100 meV in the conduction band. Electrical, magnetic, and magneto-transport measurements reveal distinct behaviors depending on EF. At lower EF values (10 meV), MnBi2Te4 exhibits degenerate-semiconductor-like electrical transport and ferrimagnetism, with weak coupling between magneto-resistance and ferrimagnetism. In contrast, MnBi2Te4 displays metallic transport and antiferromagnetism (AFM) at higher Fermi energies, with magneto-resistance strongly coupled to antiferromagnetism and canted antiferromagnetism under a large external magnetic field. Remarkably, Hall measurements demonstrate a pronounced anomalous Hall resistivity (AHR) when the EF of MnBi2Te4 is 10 meV, larger than that reported for other bulk MnBi2Te4 crystals in the literature. Significant AHR is attributed to the Berry-phase effect in electronic-band structure based on first-principles calculation. The evolution of magnetic and magneto-transport properties in EF shifted MnBi2Te4 can be semi-quantitatively explained by the Ruderman–Kittel–Kasuya–Yosida interaction between neighboring MnTe layers. Our work suggests that the strongly Fermi-energy-sensitive magneto-transport properties observed in MnBi2Te4 may be useful in developing magnetic sensors/detectors.

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