Phase diagram and evolution of the magnetic ordering state driven by a field-effect transistor in (Li,Fe)OHFeS thin flakes

Lei, Bin; K., L.; Wang, N. Z.; Zhu, Changan; Cui, Jianhua; Sun, Zhao-Yan; H., D.; Wang, H. H.; Shi, Mengzhu; Ying, Jianjun; Chen, X. H.

doi:10.1103/physrevb.100.174519

Cited by 11 publications

(6 citation statements)

References 21 publications

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“…As an example, monolayer FeSe has a particular sandwiched structure (Se-Fe-Se), and the Janus structure can be built by replacing the top Se atomic layer with S atoms (Fe 2 SSe), and then applying the gating techniques to inject a large amount of Li ions into the monolayer Fe 2 SSe (Li 2 Fe 2 SSe). The related experimental techniques have been widely used [34][35][36][37][38].…”

Section: Introductionmentioning

confidence: 99%

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Guo¹,

Mu²,

Yin³

et al. 2021

J. Phys. D: Appl. Phys.

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Recently, predictions have been made about quantum anomalous Hall (QAH) insulators in Lithium-decorated iron-based superconductor monolayer materials (LiFeX (X = S, Se and Te)) with very high Curie temperatures (0.00,0.00,1.00PRL 125, 086401 (2020)), which combine topological and ferromagnetic orders. It is interesting and useful to achieve the coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in single two-dimensional (2D) materials, namely 2D piezoelectric quantum anomalous Hall insulators (PQAHIs). In this work, 2D Janus monolayer Li2Fe2SSe is predicted to be a room-temperature PQAHI, which possesses dynamic, mechanical, and thermal stabilities. It is predicted to be a half Dirac semimetal without spin–orbit coupling (SOC). It is found that the inclusion of SOC opens up a large nontrivial gap, which means nontrivial bulk topology (QAH insulator), confirmed by the calculation of Berry curvature and the presence of two chiral edge states (Chern number C = 2). Calculated results show that the monolayer Li2Fe2SSe possesses robust QAH states against biaxial strain and electronic correlations. Compared to LiFeX, the glide mirror G z of Li2Fe2SSe disappears, which will only induce an out-of-plane piezoelectric response. The calculated out-of-plane d 31 of the monolayer Li2Fe2SSe is −0.238 pm V−1, comparable with those of other known 2D materials. Moreover, a very high Curie temperature (about 1000 K) is predicted by using Monte Carlo simulations, which means that the QAH effect can be achieved at room temperature in the Janus monolayer Li2Fe2SSe. Similar to the monolayer Li2Fe2SSe, the PQAHI can also be realized in the Janus monolayer Li2Fe2SeTe. Our work opens a new avenue in searching for PQAHIs with high temperatures and high Chern numbers, which provide a potential platform for multi-functional spintronic applications.

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Section: Introductionmentioning

confidence: 99%

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Guo¹,

Mu²,

Yin³

et al. 2021

J. Phys. D: Appl. Phys.

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“…However, all these methods have drawbacks. For example, a relatively large electric field is necessary to achieve significant bandgap modification while electrochemical modification and ion doping may strongly alter the atomic structure of the material, generating large amounts of defects or impurities. − …”

mentioning

confidence: 99%

Giant Bandgap Engineering in Two-Dimensional Ferroelectric α-In₂Se₃

Zhang

Wang

et al. 2022

J. Phys. Chem. Lett.

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Bandgap engineering is an efficient strategy for controlling the physical properties of semiconductor materials. For flexible two-dimensional (2D) materials, strain provides a nondestructive and adjustable method for bandgap adjustment. Here, we propose that, in 2D materials with out-of-plane ferroelectricity, the antibonding nature of the valence band maximum and conduction band minimum and polarized charge distribution induced by ferroelectricity give rise to giant changes of the bandgap under curvature strain field. This hypothesis was proven by scanning tunneling microscopy/spectroscopy measurements on monolayer α-In2Se3 that revealed that the bandgap of α-In2Se3 increases significantly due to bending. Both experiments and theoretical calculations indicated that the bandgap increases monotonically with the degree of bending of the α-In2Se3 layer. Our work suggests that bending is an effective method for tuning the gaps of 2D ferroelectric materials, providing a new platform for bandgap engineering under the combination of ferroelectricity and strain field.

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“…Finally let us discuss possible experimental evidences. Recent works discovered that the injection of Li into (Li,Fe)OH-FeSe and (Li,Fe)OH-FeS can induce a superconducting to ferromagnetic insulating transition, leading to the emergence of a high-T C ferromagnetism and strong anomalous Hall effects in the insulating state [71,72]. The observed effects were tentatively attributed to be caused by the Fe atoms substituted from (Li,Fe)OH.…”

Section: Prediction Of High-temperature Qah Insulator Lifesementioning

confidence: 99%

First-principles discovery of novel quantum physics and materials: From theory to experiment

2020

Preprint

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Modern material science has been revolutionized by the discovery of novel topological states of quantum matter, which sheds new lights on solving long-standing scientific challenges. However, the exotic quantum phenomena are typically observable only in rare material systems under extreme experimental conditions. The search of suitable candidate materials that are able to work at ambient conditions is thus of crucial importance to both fundamental research and practical applications. Here we review our recent efforts on first-principles exploration of novel quantum physics and materials, focusing on emergent quantum phenomena induced by spin-orbit coupling and its interplay with magnetism, topology and superconductivity. The first-principles material design guided by fundamental theory enables the discoveries of several key quantum materials, including next-generation magnetic topological insulators, high-temperature quantum anomalous Hall and quantum spin Hall insulators, and unconventional superconductors. A close collaboration with experiment not only successfully confirmed most of our theoretical predictions, but also led to surprising findings for further investigations, which greatly promotes development of the research field.

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Phase diagram and evolution of the magnetic ordering state driven by a field-effect transistor in (Li,Fe)OHFeS thin flakes

Cited by 11 publications

References 21 publications

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Giant Bandgap Engineering in Two-Dimensional Ferroelectric α-In₂Se₃

First-principles discovery of novel quantum physics and materials: From theory to experiment

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Phase diagram and evolution of the magnetic ordering state driven by a field-effect transistor in (Li,Fe)OHFeS thin flakes

Cited by 11 publications

References 21 publications

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe2SSe with a high Curie temperature

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe2SSe with a high Curie temperature

Giant Bandgap Engineering in Two-Dimensional Ferroelectric α-In2Se3

First-principles discovery of novel quantum physics and materials: From theory to experiment

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Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Coexistence of intrinsic piezoelectricity, ferromagnetism, and nontrivial band topology in Li-decorated Janus monolayer Fe₂SSe with a high Curie temperature

Giant Bandgap Engineering in Two-Dimensional Ferroelectric α-In₂Se₃