Nonreciprocal directional dichroism of a chiral magnet in the visible range

Abstract

Nonreciprocal directional dichroism is an unusual light-matter interaction that gives rise to diode-like behavior in low-symmetry materials. The chiral varieties are particularly scarce due to the requirements for strong spin-orbit coupling, broken time-reversal symmetry, and a chiral axis. Here we bring together magneto-optical spectroscopy and first-principles calculations to reveal highenergy, broadband nonreciprocal directional dichroism in Ni 3 TeO 6 with special focus on behavior in the metamagnetic phase above 52 T. In addition to demonstrating this effect in the magnetochiral configuration, we explore the transverse magnetochiral orientation in which applied field and light propagation are orthogonal to the chiral axis and, by so doing, uncover an additional configuration with a unique nonreciprocal response in the visible part of the spectrum. In a significant conceptual advance, we use first-principles methods to analyze how the Ni 2+ d-to-d on-site excitations develop magneto-electric character and present a microscopic model that unlocks the door to theory-driven discovery of chiral magnets with nonreciprocal properties.

Exploring few and single layer CrPS4 with near-field infrared spectroscopy

“…If switchable, because our findings suggest that the bulk polar mode persists down to the single-layer limit, atomically-thin CrPS 4 may realize ideal two-dimensional ferroelectricity. In addition, it is well-known that coexistence of structural chirality and magnetization leads to nonreciprocal transport of quasiparticles and collective excitations [61,62], namely diode effects. In this regard, CrPS 4 has the potential to be another rare example of a chiral magnet that exhibits nontrivial consequences of magnetoelectric coupling and intriguing lightmatter interactions.…”

Visualizing rotation and reversal of the Néel vector through antiferromagnetic trichroism

“…Generally, NDD in the (near-)visible range is explained in terms of the interference effect between electric-dipole (E1) and magnetic-dipole (M1) transitions through the spin–orbit interaction 18 – 20 , 23 , 25 – 27 . This indicates that NDD will be most pronounced when E1 and M1 transitions are comparable in magnitude with each other.…”

Magneto‐chiral anisotropy: From fundamentals to perspectives

“…In these cases, the experiment is more complex, as it is necessary to differentiate magnetoelectric responses from magneto-chiral ones. Several theoretical and experimental MChA studies using microwaves 37,38 or ultraviolet (UV)-visible [39][40][41] radiation have been reported on such materials in recent years.…”