skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Explore Research Products in the PAR
It may take a few hours for recently added research products to appear in PAR search results.


Title: Unconventional Anomalous Hall Effect Driven by Self‐Intercalation in Covalent 2D Magnet Cr 2 Te 3
Abstract Covalent 2D magnets such as Cr2Te3, which feature self‐intercalated magnetic cations located between monolayers of transition‐metal dichalcogenide material, offer a unique platform for controlling magnetic order and spin texture, enabling new potential applications for spintronic devices. Here, it is demonstrated that the unconventional anomalous Hall effect (AHE) in Cr2Te3, characterized by additional humps and dips near the coercive field in AHE hysteresis, originates from an intrinsic mechanism dictated by the self‐intercalation. This mechanism is distinctly different from previously proposed mechanisms such as topological Hall effect, or two‐channel AHE arising from spatial inhomogeneities. Crucially, multiple Weyl‐like nodes emerge in the electronic band structure due to strong spin‐orbit coupling, whose positions relative to the Fermi level is sensitively modulated by the canting angles of the self‐intercalated Cr cations. These nodes contribute strongly to the Berry curvature and AHE conductivity. This component competes with the contribution from bands that are less affected by the self‐intercalation, resulting in a sign change in AHE with temperature and the emergence of additional humps and dips. The findings provide compelling evidence for the intrinsic origin of the unconventional AHE in Cr2Te3 and further establish self‐intercalation as a control knob for engineering AHE in complex magnets.  more » « less
Award ID(s):
2242796
PAR ID:
10580586
Author(s) / Creator(s):
; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more » ; ; ; ; ; ; « less
Publisher / Repository:
Wiley
Date Published:
Journal Name:
Advanced Science
Volume:
12
Issue:
2
ISSN:
2198-3844
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
More Like this
  1. ; (, Physical Review B)
    The anomalous Hall effect (AHE) is an efficient tool for detecting the Néel vector in collinear compensated magnets with spin-split bands, known as altermagnets (AMs). Here, we establish design principles for obtaining nonzero anomalous Hall conductivity in the recently proposed two-dimensional (2D) AMs using spin and magnetic group symmetry analysis. We show that only two of the seven nontrivial spin layer groups exhibit an unconventional in-plane AHE in which the Néel vector lies within the plane of the Hall current. Through first-principles simulations on bilayers of MnPSe3 and MnSe, we demonstrate the validity of our group theoretic framework for obtaining AHE with d- and i-wave altermagnetic orders, depending on the stacking of the bilayers. We find that the spin group symmetry is successful in determining the linear and cubic dependence of anomalous Hall conductivity in Néel vector space, although AHE is a relativistic effect. This work shows that the AHE in 2D AMs can probe the altermagnetic order and Néel vector reversal, thereby facilitating the miniaturization of altermagnetic spintronics. 
    more » « less
  2. ; ; ; ; ; ; ; ; ; ; et al (, 2D Materials)
    Abstract MnBi 2 Te 4 /(Bi 2 Te 3 ) n materials system has recently generated strong interest as a natural platform for the realization of the quantum anomalous Hall (QAH) state. The system is magnetically much better ordered than substitutionally doped materials, however, the detrimental effects of certain disorders are becoming increasingly acknowledged. Here, from compiling structural, compositional, and magnetic metrics of disorder in ferromagnetic (FM) MnBi 2 Te 4 /(Bi 2 Te 3 ) n it is found that migration of Mn between MnBi 2 Te 4 septuple layers (SLs) and otherwise non-magnetic Bi 2 Te 3 quintuple layers (QLs) has systemic consequences—it induces FM coupling of Mn-depleted SLs with Mn-doped QLs, seen in ferromagnetic resonance as an acoustic and optical resonance mode of the two coupled spin subsystems. Even for a large SL separation ( n ≳ 4 QLs) the structure cannot be considered as a stack of uncoupled two-dimensional layers. Angle-resolved photoemission spectroscopy and density functional theory studies show that Mn disorder within an SL causes delocalization of electron wave functions and a change of the surface band structure as compared to the ideal MnBi 2 Te 4 /(Bi 2 Te 3 ) n . These findings highlight the critical importance of inter- and intra-SL disorder towards achieving new QAH platforms as well as exploring novel axion physics in intrinsic topological magnets. 
    more » « less
  3. ; ; ; ; ; ; ; ; ; ; et al (, Communications Physics)
    Proposed mechanisms for large intrinsic anomalous Hall effect (AHE) in magnetic topological semimetals include diverging Berry curvatures of Weyl nodes, anticrossing nodal rings or points of non-trivial bands. Here we demonstrate that a half-topological semimetal (HTS) state near a topological critical point can provide an alternative mechanism for a large AHE via systematic studies on an antiferromagnetic (AFM) half-Heusler compound TbPdBi. We not only observe a large AHE with tanΘH≈ 2 in its field-driven ferromagnetic (FM) phase, but also find a distinct Hall resistivity peak in its canted AFM phase. Moreover, we observe a large negative magnetoresistance with a value of ~98%. Our in-depth theoretical modelling indicates that these exotic transport properties originate from the HTS state which exhibits Berry curvature cancellation between the trivial spin-up and nontrivial spin-down bands. Our study offers alternative strategies for improved materials design for spintronics and other applications. 
    more » « less
  4. ; ; ; ; ; ; ; ; ; ; et al (, Nature Communications)
    Abstract Magnetic transition metal chalcogenides form an emerging platform for exploring spin-orbit driven Berry phase phenomena owing to the nontrivial interplay between topology and magnetism. Here we show that the anomalous Hall effect in pristine Cr 2 Te 3 thin films manifests a unique temperature-dependent sign reversal at nonzero magnetization, resulting from the momentum-space Berry curvature as established by first-principles simulations. The sign change is strain tunable, enabled by the sharp and well-defined substrate/film interface in the quasi-two-dimensional Cr 2 Te 3 epitaxial films, revealed by scanning transmission electron microscopy and depth-sensitive polarized neutron reflectometry. This Berry phase effect further introduces hump-shaped Hall peaks in pristine Cr 2 Te 3 near the coercive field during the magnetization switching process, owing to the presence of strain-modulated magnetic layers/domains. The versatile interface tunability of Berry curvature in Cr 2 Te 3 thin films offers new opportunities for topological electronics. 
    more » « less
  5. ; ; ; ; ; ; ; ; ; (, Applied Physics Letters)
    Non-collinear spin texture has attracted great attention since it provides an important probe of the interaction between electron and topological spin textures. While it has been widely reported in chiral magnets, oxide heterostructures, and hybrid systems such as ferromagnet/heavy metal and ferromagnet/topological insulators, the study of non-collinear spin texture in two-dimensional (2D) van der Waals (vdW) dilute magnetic semiconductor (DMS) monolayers is relatively lacking, hindering the understanding at the atomically thin scale. Here, we probe the temperature-dependent antisymmetric humps in Hall resistivity by utilizing the proximity coupling of Fe-doped monolayer WSe2 (Fe:WSe2) synthesized using chemical vapor deposition on a Pt Hall bar. Multiple characterization methods were employed to demonstrate that Fe atoms substitutionally replace W atoms, making a 2D vdW DMS at room temperature. Distinct from the intrinsic anomalous Hall effect, we found the transverse Hall resistivity of Fe:WSe2 displaying two additional antisymmetric peak features in the temperature-dependent measurements. These peaks are attributed to the magnetic features at the Fe:WSe2 and Pt interface. Our work shows that a DMS synthesized from 2D vdW transition metal dichalcogenides is promising for realizing magnetic and spintronic applications. 
    more » « less
  • Citation Formats
  • MLA
  • APA
  • Chicago
  • BibTeX
  • Text Encoded Conversion
  • XML
  • Save / Share this Record
  • Send to Email