Topic of Research Seminar: Detecting the zero-order and hidden orders

Abstract: Magnetic dipole moments are familiar to everyone in the form of bar magnets or current loops. It turns out that monopoles, which affect electric fields in all directions symmetrically, and dipoles, which describe the difference in two halves of a field, are sufficient to describe most moments produced by electric and magnetic fields. Higher-order multipoles (quadrupoles, octupoles, dodecapoles, etc.) exist and are often neglected in favor of the monopole or dipole description, often for the sake of simplicity or to make calculations more manageable.

Over the years, it has become clear that higher-order multipoles may be playing a significant role in a variety of materials that exhibit an invisible or “hidden order” of electronic origin, but their experimental realization is still an open challenge due to the insensitivity of the existing tools to these higher order multipoles.

I will talk about my current ongoing research activities for the advancement of a new technique, resonant torsion magnetometry, to explicitly detect higher-order multipoles in the Pr-based cage compounds PrT2Al20(T= V, Ti). The detection and overall understanding of the higher-order multipoles could lead to the resolution of several longstanding mysteries in condensed matter physics and specifically related to the new material properties such as superconductivity and quantum spin liquid states which are both crucial in the realization of energy-efficient devices and robust topological quantum computers.

Subject Field of Topic: Magnetism

Name of Speaker: Dr. Muhammad Nouman Kakakhail

Professorial Rank of Speaker: Assistant Professor

Email of Speaker: [email protected]

Affiliation of Speaker: NUST School of Natural Sciences, National University of Sciences and Technology (NUST-SNS)

Venue and Date: Sept 19, 2023, (Tuesday), at 1500 hrs, in CR # 202, New Building, School of Natural Sciences (SNS), NUST Islamabad Campus