Pressure tuning of the anomalous Hall effect in the kagome superconductor CsV₃Sb₅

Abstract

Controlling the anomalous Hall effect (AHE) inspires potential applications of quantum materials in the next generation of electronics. The recently discovered quasi-2D kagome superconductor CsV3Sb5 exhibits large AHE accompanying with the charge-density-wave (CDW) order which provides us an ideal platform to study the interplay among nontrivial band topology, CDW, and unconventional superconductivity. Here, we systematically investigated the pressure effect of the AHE in CsV3Sb5. Our high-pressure transport measurements confirm the concurrence of AHE and CDW in the compressed CsV3Sb5. Remarkably, distinct from the negative AHE at ambient pressure, a positive anomalous Hall resistivity sets in below 35 K with pressure around 0.75 GPa, which can be attributed to the Fermi surface reconstruction and/or Fermi energy shift in the new CDW phase under pressure. Our work indicates that the anomalous Hall effect in CsV3Sb5 is tunable and highly related to the band structure.

Chiral charge density wave induced by mirror symmetry breaking in kagome metal

“…It is in agreement with the reported observation that both the electron and phonon play a role in the formation of CDW [37]. Very recently, through the zerofield muon spin relaxation technique, an intrinsic local magnetic field was observed in the 2 × 2 CDW phase of CsV 3 Sb 5 [25]. However, no measurable local spin moments or magnetic correlations can be responsible for it.…”

“…In particular, the 2 × 2 CDW shows a novel chirality, where the electron occupation exhibits an 'A-B-C-A-B-C' structure at the six vertices of the hexagonal cell, and the chirality is defined as the clockwise or anticlockwise direction from the minimum to maximum of electron occupations. Furthermore, the chirality can be modulated unusually by the magnetic field, which indicates that the time inversion symmetry of the system is broken [24][25][26]. In correlated electron systems, chirality usually occurs in static spin system or dynamic current system [27], while it is rare in static charge system.…”

Intertwining orbital current order and superconductivity in kagome metal

“…In recent high pressure experiments, it was shown that the suppression of CDW leads to the enhanced superconductivity upon increasing pressure and a second superconducting dome appears at even higher pressures [14,47,48,50,[53][54][55][56]. It will be interesting to establish precise relationship between the onset temperature of the anomalous Hall effect and superconductivity as well as CDW in pressurized systems.…”

Intertwining orbital current order and superconductivity in Kagome metal

“…In recent high pressure experiments, it was shown that the suppression of CDW leads to the enhanced superconductivity upon increasing pressure and a second superconducting dome appears at even higher pressures [14,50,51,53,[56][57][58][59]. It will be interesting to establish precise relationship between the onset temperature of the anomalous Hall effect and superconductivity as well as CDW in pressurized systems.…”