Carmine ORTIX(University of Salerno)
- 10 Fév 2022
- 11h00 - 12h00
C. ORTIX: Non-linear and anomalous planar Hall effect in Dirac materials
It has been recently established that Hall-like transverse currents can appear as a second-order response to an external electric field in a wide class of time-reversal symmetric and inversion-symmetry broken materials . This non-linear Hall effect possesses a quantum contribution directly arising from the dipole moment of the Berry curvature, and has been recently observed in two-dimensional materials with strong spin-orbit coupling where the low-energy Dirac quasiparticles form tilted Dirac cones. I will show that this topological effect can appear even in absence of spin-orbit coupling . In such systems, it is the warping of the Fermi surface that triggers sizeable Berry curvature dipoles. As a prominent example, I will show that uniaxially strained bilayer graphene with gate-induced bandgaps has dipoles comparable in strength to those observed in bilayer transition metal dichalcogenides . In the second part of the talk, I will show that the Berry curvature in two-dimensional trigonal crystals can yield an anomalous planar Hall effect  producing a transverse current even in a configuration where the driving electric field is aligned with the external magnetic field.
 C. Ortix, Advanced Quantum Technologies 2100056 (2021).
 R. Battilomo, N. Scopigno, C. Ortix, PRL 123, 196403 (2019).
 S.-C. Ho, …, C. Ortix, T.-M. Chen, Nature Electronics 4, 116 (2021).
 R. Battilomo, N. Scopigno, C. Ortix, Phys.Rev.Research 3, L012006(2021)