High-spin configuration of Mn in Bi2Se3 three-dimensional topological insulator

Wołoś, Agnieszka; Drabińska, Aneta; Borysiuk, J.; Sobczak, Kamil; Kamińska, M.; Hruban, A.; Strzelecka, S.; Materna, A.; Piersa, M.; Romaniec, M.; Diduszko, R.

doi:10.1016/j.jmmm.2016.06.017

Cited by 10 publications

(9 citation statements)

References 31 publications

(49 reference statements)

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“…A plausible scenario for the experimentally observed weak dependence of T C on Mn concentration could thus be based on a simultaneous increase of both Mn Bi and Mn i . Another explanation may be due to the influence of Mn doping on native defects, which has already been suggested 15,23,80 . Therefore we also performed calculations of the system in the presence of the most probable native impurities.…”

Section: Discussionmentioning

confidence: 91%

“…Samples with p-type conductivity have also been found, namely in Ca-counterdoped samples 38 and in some of the Mn-doped samples 24,25,39 . There is a general agreement that the most probable defect responsible for increasing the Fermi level are V Se , Se vacancies 15,38,40 . This is supported by ab initio calculations of defect formation energies 41,42 .…”

Section: Introductionmentioning

confidence: 97%

“…Due to the strong spin-orbit coupling the direction of electron movement is coupled to its spin in the vicinity of the Dirac point 1,6 . Recently, mutual interaction between these surface states and magnetism has become a subject targeted by many research studies [7][8][9][10][11][12][13][14][15][16][17][18][19] . When magnetic order is introduced into bulk TI, the time reversal symmetry is broken.…”

Section: Introductionmentioning

confidence: 99%

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Magnetic properties of Mn-doped Bi2Se3 topological insulators: Ab initio calculations

Carva¹,

Baláž²,

Šebesta³

et al. 2020

Phys. Rev. B

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Doping Bi2Se3 by magnetic ions represents an interesting problem since it may break the time reversal symmetry needed to maintain the topological insulator character. Mn dopants in Bi2Se3 represent one of the most studied examples here. However, there is a lot of open questions regarding their magnetic ordering. In the experimental literature different Curie temperatures or no ferromagnetic order at all are reported for comparable Mn concentrations. This suggests that magnetic ordering phenomena are complex and highly susceptible to different growth parameters, which are known to affect material defect concentrations. So far theory focused on Mn dopants in one possible position, and neglected relaxation effects as well as native defects. We have used ab initio methods to calculate the Bi2Se3 electronic structure influenced by magnetic Mn dopants, and exchange interactions between them. We have considered two possible Mn positions, the substitutional and interstitial one, and also native defects. We have found a sizable relaxation of atoms around Mn, which affects significantly magnetic interactions. Surprisingly, very strong interactions correspond to a specific position of Mn atoms separated by van der Waals gap. Based on the calculated data we performed spin dynamics simulations to examine systematically the resulting magnetic order for various defect contents. We have found under which conditions the experimentally measured Curie temperatures TC can be reproduced, noticing that interstitial Mn atoms appear to be important here. Our theory predicts the change of TC with a shift of Fermi level, which opens the way to tune the system magnetic properties by selective doping.

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Section: Discussionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Magnetic properties of Mn-doped Bi2Se3 topological insulators: Ab initio calculations

Carva¹,

Baláž²,

Šebesta³

et al. 2020

Phys. Rev. B

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“…Taking into account that the real samples exhibit conductivity of n-type, we expect that they act as acceptors and exist in 2+ charge state. Indeed, Mn 2+ signal with magnetic moment of 5µ B in Bi 2 Se 3 was observed by EPR measurements [84]. The Mn 2+ level is located within the valence band [see Fig.…”

Section: Interplay Between Impurity Levels and Topological Surface St...mentioning

confidence: 97%

Electronic properties of Bi$_{2}$Se$_{3}$ dopped by $3d$ transition metal (Mn, Fe, Co, or Ni) ions

Ptok,

Kapcia,

Ciechan

2020

Preprint

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Topological insulators are characterized by the existence of band inversion and the possibility of the realization of surface states. Doping with a magnetic atom, which is a source of the timereversal symmetry breaking, can lead to realization of novel magneto-electronic properties of the system. In this paper, we study effects of substitution by the transition metal ions (Mn, Fe, Co and Ni) into Bi2Se3 on its electric properties. Using the ab inito supercell technique, we investigate the density of states and the projected band structure. Under such substitution the shift of the Fermi level is observed. We find the existence of nearly dispersionless bands around the Fermi level associated with substituted atoms, especially, in the case of the Co and Ni. Additionally, we discuss the modification of the electron localization function as well as charge and spin redistribution in the system. Our study shows a strong influence of the transition metal-Se bond on local modifications of the physical properties. The results are also discussed in the context of the interplay between energy levels of the magnetic impurities and topological surface states.

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“…Se

), where Bi atoms replace Se ones and vice versa. This non-stoichiometry arises due to difficulties in controlling growth conditions, which result in Bi- or Se- rich samples [ 23 , 33 , 34 , 35 , 36 ]. It has been shown that not only the magnetic defects, but also nonmagnetic disorder can substantially modify the dispersion of the Dirac surface states.…”

Section: Introductionmentioning

confidence: 99%

Twin Domain Structure in Magnetically Doped Bi2Se3 Topological Insulator

et al. 2020

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Twin domains are naturally present in the topological insulator Bi2Se3 and strongly affect its properties. While studies of their behavior in an otherwise ideal Bi2Se3 structure exist, little is known about their possible interaction with other defects. Extra information is needed, especially for the case of an artificial perturbation of topological insulator states by magnetic doping, which has attracted a lot of attention recently. Employing ab initio calculations based on a layered Green’s function formalism, we study the interaction between twin planes in Bi2Se3. We show the influence of various magnetic and nonmagnetic chemical defects on the twin plane formation energy and discuss the related modification of their distribution. Furthermore, we examine the change of the dopants’ magnetic properties at sites in the vicinity of a twin plane, and the dopants’ preference to occupy such sites. Our results suggest that twin planes repel each other at least over a vertical distance of 3–4 nm. However, in the presence of magnetic Mn or Fe defects, a close twin plane placement is preferred. Furthermore, calculated twin plane formation energies indicate that in this situation their formation becomes suppressed. Finally, we discuss the influence of twin planes on the surface band gap.

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High-spin configuration of Mn in Bi2Se3 three-dimensional topological insulator

Cited by 10 publications

References 31 publications

Magnetic properties of Mn-doped Bi2Se3 topological insulators: Ab initio calculations

Magnetic properties of Mn-doped Bi2Se3 topological insulators: Ab initio calculations

Electronic properties of Bi$_{2}$Se$_{3}$ dopped by $3d$ transition metal (Mn, Fe, Co, or Ni) ions

Twin Domain Structure in Magnetically Doped Bi2Se3 Topological Insulator

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