First-principles Theory of Magnetic Multipoles in Condensed Matter Systems

Suzuki, Michi To; Ikeda, Hiroaki; Oppeneer, Peter M.

doi:10.7566/jpsj.87.041008

Cited by 88 publications

(60 citation statements)

References 422 publications

(518 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This method has been implemented in a computer program 61,62 , which generates the shape of linear response tensors (IAHC or intrinsic spin Hall conductivity) in a given coordinate system. Another useful analysis tool is the so-called cluster multipole theory 23,24 , which is capable of uncovering the hidden AHE in AFMs by evaluating the cluster multipole moment that behaves as a macroscopic magnetic order. For instance, although the cluster dipole moments (i.e., the net magnetization from the conventional understanding) vanish in noncollinear AFMs (e.g., Mn 3 X and Mn 3 Y ), the emerging cluster octupole moments lead to a finite AHE.…”

Section: Group Theory Analysismentioning

confidence: 99%

Spin-order dependent anomalous Hall effect and magneto-optical effect in the noncollinear antiferromagnets Mn3XN with X=Ga , Zn, Ag, or Ni

et al. 2019

View full text Add to dashboard Cite

The anomalous Hall effect (AHE) and the magneto-optical effect (MOE) are two prominent manifestations of time-reversal symmetry breaking in magnetic materials. Noncollinear antiferromagnets (AFMs) have recently attracted a lot of attention owing to the potential emergence of exotic spin orders on geometrically frustrated lattices, which can be characterized by corresponding spin chiralities. By performing first-principles density functional calculations together with group-theory analysis and tight-binding modelling, here we systematically study the spin-order dependent AHE and MOE in representative noncollinear AFMs Mn3XN (X = Ga, Zn, Ag, and Ni). The symmetry-related tensor shape of the intrinsic anomalous Hall conductivity (IAHC) for different spin orders is determined by analyzing the relevant magnetic point groups. We show that while only the xy component of the IAHC tensor is nonzero for right-handed spin chirality, all other elements − σxy, σyz, and σzx − are nonvanishing for a state with left-handed spin chirality owing to lowering of the symmetry. Our tight-binding arguments reveal that the magnitude of IAHC relies on the details of the band structure and that σxy is periodically modulated as the spin rotates in-plane. The IAHC obtained from first principles is found to be rather large, e.g., it amounts to 359 S/cm in Mn3AgN, which is comparable to other well-known noncollinear AFMs such as Mn3Ir and Mn3Ge. We evaluate also the magnetic anisotropy energy and find that the evolution of spin order is related to the number of valence electrons in the X ion. Interestingly, the left-handed spin chirality could exist in Mn3XN with some particular spin configurations. By extending our analysis to finite frequencies, we calculate the optical isotropy [σxx(ω) ≈ σyy(ω) ≈ σzz(ω)] and the magnetooptical anisotropy [σxy(ω) = σyz(ω) = σzx(ω)] of Mn3XN. Similar to the IAHC, the magneto-optical Kerr and Faraday spectra depend strongly on the spin order. The Kerr rotation angles in Mn3XN are in the range of 0.3 ∼ 0.4 deg, which is large and comparable to other noncollinear AFMs like Mn3Pt and Mn3Sn. Our finding of large AHE and MOE in Mn3XN suggests that these materials present an excellent antiferromagnetic platform for realizing novel spintronics and magneto-optical devices. We argue that the spin-order dependent AHE and MOE are indispensable in detecting complex spin structures in noncollinear AFMs. arXiv:1903.11038v1 [cond-mat.mtrl-sci]

show abstract

Section: Group Theory Analysismentioning

confidence: 99%

Spin-order dependent anomalous Hall effect and magneto-optical effect in the noncollinear antiferromagnets Mn3XN with X=Ga , Zn, Ag, or Ni

et al. 2019

View full text Add to dashboard Cite

show abstract

“…(1) and (2). First-principles calculations are powerful tools for a quantitative estimation of ME effects [70,71] and magnetic multipole moments [28,29,[72][73][74][75].…”

Section: Magnetoelectric Effectmentioning

confidence: 99%

Group-theoretical classification of multipole order: Emergent responses and candidate materials

2018

View full text Add to dashboard Cite

The multipole moment is an established concept of electrons in solids. Entanglement of spin, orbital, and sublattice degrees of freedom is described by the multipole moment, and spontaneous multipole order is a ubiquitous phenomenon in strongly correlated electron systems. In this paper, we present group-theoretical classification theory of multipole order in solids. Intriguing duality between the real space and momentum space properties is revealed for odd-parity multipole order which spontaneously breaks inversion symmetry. Electromagnetic responses in odd-parity multipole states are clarified on the basis of the classification theory. A direct relation between the multipole moment and the magnetoelectric effect, Edelstein effect, magnetopiezoelectric effect, and dichromatic electron transport is demonstrated. More than 110 odd-parity magnetic multipole materials are identified by the group-theoretical analysis. Combining the list of materials with the classification tables of multipole order, we predict emergent responses of the candidate materials. arXiv:1805.10828v2 [cond-mat.mtrl-sci]

show abstract

“…Especially, there is a lack of systematic methods to obtain its effective model so far. Here, we propose a framework to derive an effective model of noncollinear AFM based on the cluster multipole theory [33,39,40]. In Mn 3 Sn, the derived model is composed of two octupole degrees of freedom and reduced into the sine-Gordon model similar to FM and collinear AFM.…”

mentioning

confidence: 99%