November: Anuva Aishwarya

The curious case of the magnetic field-sensitive charge density waves in UTe2

Anuva Aishwarya

Harvard University (Yacoby group)

Wednesday, November 15

2:00 pm ET/11:00 am PT

Abstract:

Coexisting or competing broken symmetry phases in unconventional superconductors is an area of continuous focus in condensed matter physics. UTe2 is a heavy fermion superconductor that exhibits a rich low-temperature phase diagram owing to strong correlations in this material. In this talk, I am going to talk about our discovery of a multicomponent charge-density wave (CDW) order employing scanning tunneling microscopy (STM). We show that the CDW is unconventional due to its sensitivity to magnetic field and disappears at superconducting Hc2. One possible explanation for this behavior invokes the presence of a pair density wave state (PDW). The PDW scenario suggests that any vortex in the uniform superconducting phase or the PDW phase will result in topological point defects i.e., dislocations in the CDW. I will also talk about our recent work where we visualize the magnetic field induced melting of the CDW order through amplitude and phase maps from the Fourier transforms. Using the phase maps, we can identify the presence of topological defects (dislocations in the CDW) with opposite phase winding. We show that the number of these topological defects increases with increasing magnetic field and that these defects are directly responsible for destroying the CDW order. This is consistent with the existence of a PDW state in this strongly correlated superconductor. 

Bio:

Anuva Aishwarya is a postdoctoral fellow at Harvard University working in the group of Prof. Amir Yacoby. She is interested in probing strongly correlated electron systems and unconventional superconductors using scanning probe techniques. Anuva obtained her Bachelor of Science degree with a major in Physics from the Indian Institute of Science, Bengaluru in 2017. She obtained her Ph.D. in Physics from University of Illinois, Urbana-Champaign in 2023, where she worked in the group of Prof. Vidya Madhavan studying various strongly correlated electron systems using low temperature scanning tunneling microscopy.