Giant magnetoresistance in high-mobility Dirac Plasma
Magnetoresistance (MR), the change in electrical resistance under an external magnetic field, has important applications in magnetic sensing technology, as well as offering insights into poorly understood physics. Dirac semi-metals, like graphene, show promise for large intrinsic magnetoresistance. On the other hand, many fascinating phenomena, such as quantum critical conductivity and hydrodynamic flow, tend to occur around graphene's Dirac point. In this talk, Dr. Lourembam will present their latest research on giant MR around graphene's Dirac point. The Dirac plasma exhibits giant quadratic MR, reaching over 100% in fields as low as 0.1T at room temperature (RT). This is orders of magnitude larger than any other known system at RT. This unique feature of graphene is due to its massless dispersion spectrum and ultrahigh mobility, despite "Planckian-limit" scattering. As Landau quantization sets in with increasing magnetic field, giant linear MR emerges, reaching approximately 13,000% in 12T at RT. This linear MR is practically independent of temperature and can be suppressed by a proximity gate, indicating a many-body origin. Parallels with MR in strange metals are suggested, emphasizing the need to further explore "Planckian-limit" scattering in other quantum-critical 2D systems. Additionally, he will briefly discuss other high-temperature quantum transport such as Brown-Zak oscillations in these systems.
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- 21 Nanyang Link
- Singapore, Singapore
- Singapore 637371
- Starts 10 July 2023 04:33 AM UTC
- Ends 25 July 2023 04:33 AM UTC
- No Admission Charge
Speakers
James of Department of Physics and Astronomy, National Graphene Institute University of Manchester, United Kingdom
Giant magnetoresistance in high-mobility Dirac Plasma
Magnetoresistance (MR), the change in electrical resistance under an external magnetic field, has important applications in magnetic sensing technology, as well as offering insights into poorly understood physics. Dirac semi-metals, like graphene, show promise for large intrinsic magnetoresistance. On the other hand, many fascinating phenomena, such as quantum critical conductivity and hydrodynamic flow, tend to occur around graphene's Dirac point. In this talk, Dr. Lourembam will present their latest research on giant MR around graphene's Dirac point. The Dirac plasma exhibits giant quadratic MR, reaching over 100% in fields as low as 0.1T at room temperature (RT). This is orders of magnitude larger than any other known system at RT. This unique feature of graphene is due to its massless dispersion spectrum and ultrahigh mobility, despite "Planckian-limit" scattering. As Landau quantization sets in with increasing magnetic field, giant linear MR emerges, reaching approximately 13,000% in 12T at RT. This linear MR is practically independent of temperature and can be suppressed by a proximity gate, indicating a many-body origin. Parallels with MR in strange metals are suggested, emphasizing the need to further explore "Planckian-limit" scattering in other quantum-critical 2D systems. Additionally, he will briefly discuss other high-temperature quantum transport such as Brown-Zak oscillations in these systems.