Berry curvature engineering by gating two-dimensional antiferromagnets

Electric and magnetic fields tuned spin-polarized topological phases in two-dimensional ferromagnetic MnBi$_4$Te$_7$

“…This approach is reliable and effective for studying the magnetic field induced evolution of topological states [74,75]. Our DFT calculations on the electronic properties indicate that the MnBi 4 Te 7 monolayer possesses a FM groundstate with a saturation magnetic moment of ∼5.00 µ B , which matches well with prior results [34,76]. The spin-polarized electronic band structure of MnBi 4 Te 7 in the absence of SOC is shown in Fig.…”

“…As is well known, applying an external field such as electric or magnetic fields is widely used to not only tune topological states but also facilitate their observations in experiments [11,15,[47][48][49][50][51][52][53][54][55][56]. For instance, the observed temperature of QAH effects in the five-septuplelayer MnBi 2 Te 4 film under a small magnetic field can remarkably be increased up to 6.5 K [11], and the combi- nation of a magnetic field and back gate voltage can give rise to a high-Chern-number QAH effect in ten-septuplelayer MnBi 2 Te 4 film [57] or drive a phase transition from the axion insulating phase to the QAH phase in the sixseptuple-layer MnBi 2 Te 4 film [56,58] at relatively high temperatures.…”

Electrically and magnetically switchable nonlinear photocurrent in РТ-symmetric magnetic topological quantum materials

“…S4. Tight-binding Hamiltonian was not directly symmetrized, however, we carefully inspect the resulted electronic structure by comparing the calculated band structures with the recent publications by Li et al 4 and Du et al 41 and our calculations are in good agreement with their results. Second, the electronic band structure of bilayer AFM-z MBT (Fig.…”

“…Then the phase effect is absent and the shift vector and Berry curvature become zero in 𝒫𝒯-symmetric system. However, one can apply Berry curvature engineering via electric gating to break the 𝒫𝒯 symmetry symmetry in the pristine bilayer MnBi2Te4 28 . Here we apply an external electric field along the out of plane direction to bilayer MnBi2Te4.…”

Layer Hall effect in a 2D topological Axion antiferromagnet

“…Compared to its prominent role in areas above, AFM has not featured prominently in the field of topological materials. However, recent theoretical works [2,3,7,11,12,[16][17][18][19][20][21][22][23][24][25] have increasingly recognized this exciting prospect. A multitude of fundamentally new topological phenomena that uniquely arise from the interplay between AFM and topology, including the condensed matter realization of Axions (a Dark matter candidate) [26], the generation of dissipationless spin current in the absence of a concomitant charge current [19], as well as the presence of giant/quantized magneto-electric and magneto-optoelectronic couplings [16,20,21,24,25], have been proposed.…”