Emergence of magnetic topological states in topological insulators doped with magnetic impurities

Tran, Minh-Tien; Nguyen, Hong-Son; Le, Duc-Anh

doi:10.1103/physrevb.93.155160

Cited by 11 publications

(20 citation statements)

References 44 publications

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“…Since the discovery of TIs, considerable experimental effort has been dedicated to achieve long-range magnetic order in two prototypical TIs, Bi 2 Se 3 and Bi 2 Te 3 , by doping with different TM atoms, such as Cr, Mn, or Fe, in both bulk and thin film geometries [17][18][19][20][21][22][23][24][25][26][27]. Significant theoretical work has also been undertaken to understand the mechanism of magnetism in transition metal (TM) doped TIs [28][29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. For some of the magnetic TIs where the QAHE has been observed, such as Cr-doped (Bi,Sb) 2 Te 3 , it has been proposed that the mechanism driving the ferromagnetic transition is based on the Van Vleck spin susceptibility [4].…”

Section: Introductionmentioning

confidence: 99%

Systematics of electronic and magnetic properties in the transition metal doped Sb2Te3 quantum anomalous Hall platform

et al. 2018

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The quantum anomalous Hall effect (QAHE) has recently been reported to emerge in magnetically doped topological insulators. Although its general phenomenology is well established, the microscopic origin is far from being properly understood and controlled. Here, we report on a detailed and systematic investigation of transition metal (TM) doped Sb 2 Te 3. By combining density functional theory calculations with complementary experimental techniques, i.e., scanning tunneling microscopy, resonant photoemission, and x-ray magnetic circular dichroism, we provide a complete spectroscopic characterization of both electronic and magnetic properties. Our results reveal that the TM dopants not only affect the magnetic state of the host material, but also significantly alter the electronic structure by generating impurity-derived energy bands. Our findings demonstrate the existence of a delicate interplay between electronic and magnetic properties in TM doped topological insulators. In particular, we find that the fate of the topological surface states critically depends on the specific character of the TM impurity: while V-and Fe-doped Sb 2 Te 3 display resonant impurity states in the vicinity of the Dirac point, Cr and Mn impurities leave the energy gap unaffected. The single-ion magnetic anisotropy energy and easy axis, which control the magnetic gap opening and its stability, are also found to be strongly TM impurity dependent and can vary from in plane to out of plane depending on the impurity and its distance from the surface. Overall, our results provide general guidelines for the realization of a robust QAHE in TM doped Sb 2 Te 3 in the ferromagnetic state.

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Section: Introductionmentioning

confidence: 99%

Systematics of electronic and magnetic properties in the transition metal doped Sb2Te3 quantum anomalous Hall platform

et al. 2018

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“…The details of numerical calculations are presented elsewhere [10]. Actually, we treat the localized electron spin classically and set S 2 i = 1 as usually adopted in many studies of magnetic materials [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. We calculate Ω for different trial states which are generated by all arranges of localized electron spins within the 3 × 3 unit cell, and find its lowest value [10].…”

Section: Bogoliubov Variational Principle and Numerical Resultsmentioning

confidence: 99%

Magnetic competition with different spin chiralities in kagome magnets

Thanh

Sơn²,

Tien

2022

J. Phys.: Conf. Ser.

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Using the Bogoliubov variational method we study the magnetic competition in a minimal model proposed for kagome magnets. The minimal model consists of itinerant electrons with their spin-orbit coupling and localized electrons with their anisotropic spin exchange. A spin exchange between localized and itinerant electrons is also included into the model, and it is anisotropic. At half filling and in the region of stable in-plane antiferromagnetism, a magnetic competition between antiferromagnetic phases with different spin chiralities is found. Depending on the sign of the hopping integral and the spin-orbit coupling, either the 1 × 1 or 3 × 3 in-plane antiferromagnetism is established. These in-plane antiferromagnetic states are characterized by distinguishable spin chiralities.

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“…The Hund coupling essentially describes the double exchange processes between itinerant electrons and localized spins [14,15]. As widely adopted in the studies of magnetic materials, we will treat the localized spins classically [14,15,[21][22][23][24][25][26][27][28][29][30][31][32].In addition, we omit the nearest-neighbor interactions between itinerant electrons and localized spins. They would be weaker than the local Hund coupling.…”

Section: Modelmentioning

confidence: 99%

“…It (Φ ≠ 0, π) induces topologically nontrivial band structure [4,5]. When the Hund coupling is included, its interplay with the SOC can emerge topological magnetic phases [31,32]. Hamiltonian (2) is just the spin version of the quantum anomalous Hall model, which is obtained from the double exchange model in the strong Hund coupling limit [4].…”

Section: Modelmentioning

confidence: 99%

Magnetic competition in topological kagome magnets

Tran

Nguyen

Nguyen³

et al. 2021

Mater. Res. Express

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Magnetic competition in topological kagome magnets is studied by incorporating the spin-orbit coupling, anisotropic Hund coupling and spin exchange into a tight-binding electron dynamics in the kagome lattice. Using the Bogoliubov variational principle we ﬁnd the stable phases at zero and ﬁnite temperatures. At zero temperature and in the strong Ising-Hund coupling regime, a magnetic tunability from the out-of-plane ferromagnetism to the in-plane antiferromagnetism is achieved through a universal property of the critical in-plane Hund coupling. At low temperature the out-of-plane ferromagnetism is stable until a ﬁnite crossing temperature. Above the crossing temperature the in-plane antiferromagnetism is stable, but the magnetization of the out-of-plane ferromagnetism still survives. This suggests a metastable coexistence of these magnetic phases in a ﬁnite temperature range. A large anomalous Hall conductance is observed in the Ising-Hund coupling limit.

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Emergence of magnetic topological states in topological insulators doped with magnetic impurities

Cited by 11 publications

References 44 publications

Systematics of electronic and magnetic properties in the transition metal doped Sb2Te3 quantum anomalous Hall platform

Systematics of electronic and magnetic properties in the transition metal doped Sb2Te3 quantum anomalous Hall platform

Magnetic competition with different spin chiralities in kagome magnets

Magnetic competition in topological kagome magnets

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