Pressure-tunable large anomalous Hall effect of the ferromagnetic kagome-lattice Weyl semimetal Co3Sn2S2

Abstract

We investigate the pressure evolution of the anomalous Hall effect in magnetic topological semimetal Co3Sn2S2 in diamond anvil cells with pressures up to 44.9-50.9 GPa. No evident trace of structural phase transition is detected through synchrotron x-ray diffraction over the measured pressure range of 0.2-50.9 GPa. We find that the anomalous Hall resistivity and the ferromagnetism are monotonically suppressed as increasing pressure and almost vanish around 22 GPa. The anomalous Hall conductivity varies non-monotonically against pressure at low temperatures, involving competition between original and emergent Weyl nodes. Combined with first-principle calculations, we reveal that the intrinsic mechanism due to the Berry curvature dominates the anomalous Hall effect under high pressure.Topological semimetals possess a nontrivial band topology in momentum space, leading to many novel properties such as chiral magnetic effect, ultrahigh mobility, negative longitudinal magnetoresistance and threedimensional quantum Hall effect [1][2][3][4][5]. Recently, nonmagnetic topological semimetals have been predicted in a large amount of crystals through first-principle calculations [6][7][8], some of which have been confirmed experimentally. However, realistic intrinsic magnetic topological semimetals are extremely rare. The entanglement between magnetism and nontrivial topology could further enrich the physical properties of quantum states, resulting in exotic transport phenomena such as large anomalous Hall effect (AHE) [9][10][11]. The AHE, usually driven by the spontaneous magnetization rather than an external magnetic field, not only deepens the understanding of topology and geometry of Bloch electrons in crystals without time reversal symmetry [12,13] but also inspires potential applications of quantum materials in next generation electronics [14,15].Very recently, a series of experiments suggest that Shandite-type compound Co 3 Sn 2 S 2 can be a magnetic Weyl semimetal and shows a giant anomalous Hall conductivity (AHC) [16,17]. Co 3 Sn 2 S 2 consists of Co 3 Sn layers sandwiched by sulfur atoms. It is known as a halfmetallic ferromagnet, whose magnetism originates from the magnetic cobalt atoms on a kagome lattice in the a-b plane with the spontaneous polarization along the c axis [18][19][20]. The interplay between this out-of-plane magnetization and the nontrivial topology of the Bloch bands accounts for the novel electromagnetic responses [16,17,[21][22][23][24][25][26]. Pressure has proven to be an effective and clean means to tune the lattice and electron degrees of freedom in topological materials. There have been several reports on pressure tuning of anomalous transports like in dilute magnetic semiconductor (In, Mn)Sb [27][28][29] and MnSi [30]. To the best of our knowledge, the highest pressure achieved is generally smaller than 3 GPa. The studies on how higher pressures modify the anomalous Hall transports in quantum materials are highly desirable. In addition, unlike the conventional element substitution meth...

Atomic disorder and Berry phase driven anomalous Hall effect in Co2FeAl Heusler compound

“…where α skew and σ int correspond to skew scattering parameter and intrinsic AHC respectively. σ int was estimated ∼ 155 S/cm, which is about 70% of total AHC at 2 K. Thus, in the present system intrinsic Berry phase driven K-L contribution dominates along with finite skew scattering [2,[56][57][58].…”

Putative helimagnetic phase in the kagome metal Co_3Sn_2-xIn_xS_2

“…It seems that In-doping affects the competing interactions such that it promotes the HM state. We note that hydrostatic pressure also causes a suppression of both FM and AFM states [34], but a pressure as high as 20 GPa is needed at which both orders are suppressed simultaneously. No HM phase was induced by pressure.…”

“…The dashed lines are linear fits to the data. The linear suppression of the critical temperature is taken following the previous work [34]. (c) The pressure dependence of the pressure induced absolute shift in critical temperature ∆TC2,onset = TC2,onset(p) -TC2,onset(0).…”

Anomalous Hall effect from gapped nodal line in Co2FeGe Heusler compound

“…4b shows variation of longitudinal conductivity and AHC with temperature. AHC is nearly insensitive to temperature from several K to 300K, while the longitudinal resistivity shows explicit temperature dependence, fairly indicates the origin of AHE governed by the intrinsic mechanism [64,68,69]. Since the intrinsic AHE merely depends on the band structure of material so to get a better understanding of the origin of intrinsic AHE, we carried out first principles calculation on Co 2 FeGe .…”