Physics 838 Graduate Student Seminar

In 1990, a seminar was initiated for QMC (formerly CNAM/CSR) graduate students in order to present their research to the other students, postdocs, and faculty in the Center. In addition to fostering a rich, collaborative environment in which students learn about the breadth and scope of research being done in QMC, the idea of this series is to teach several crucial skills to our students:

1) How to present their research in a clear and time-efficient way to an audience that was not expert in their area of research;

2) How to best answer questions during their presentations;

3) How to ask good questions when in an audience (or interview), in particular about research beyond their own narrow PhD topic.

In this seminar, students submit formalized feedback to each weekly presenter, providing informative information about presentation style, research content and tips for improvement.

Best Speaker Awards

At the end of each term, a cash prize award is given for the best student and postdoc presentations based on class feedback scores. Previous winners are listed here:

2023 (fall) Jared Erb (student), Peter Czajka (postdoc)

2022 (fall) Sungha Baek (student), Keenan Avers (postdoc)

2020 (fall) Shukai Ma 

2019 (spring) Rui Zhang (student), Tarapada Sarkar (postdoc)

2018 (fall) Chris Eckberg (student), Jen-Hao Yeh (postdoc)

2015 Paul Syers, Jasper Drisko

2014 Sean Fackler, Paul Syers,

2013 Kevin Kirshenbaum, Kirsten Burson

2012 Baladitya Suri, Kristen Burson

2011 (fall) Sergii Pershoguba, Ted Thorbeck

2011 (spring) Anirban Gangopadhyay, Baladitya Suri

2010 (fall) Christian J. Long, Tomasz M. Kott

2010 (spring) Tomasz M. Kott, Kevin Kirshenbaum

2009 (fall) Arun Luykx, Jen-Hao Yeh

PHYS838C Seminar: Jarryd Horn

Calendar
Physics 838 Seminar
Date
03.31.2025 4:00 pm - 5:00 pm
Location
John S. Toll Room 1201

Description


Title: Magnetotransport and the spin state of FeSb2



Abstract: Motivated by the recent discovery of metallic surface states in the d-electron Kondo insulator candidates FeSi and FeSb2, along with some recent reports of magnetic correlations in the surface transport properties of FeSi, we have investigated the low temperature surface magnetotransport properties of FeSb2. By using a Corbino disk transport geometry, we were able to isolate the electrical transport properties of a single surface of our samples and study the [110] and [101] naturally forming faces separately. Studying the relationship between the applied magnetic field, current direction and crystal symmetry have allowed us to separate possible contributions to the magnetotransport anisotropy. Unlike previous study of SmB6 surface states, we find no 2D Drude-like dependence on current-field direction but instead magnetocrystalline anisotropy that appears to originate from local moment scattering with a well defined easy-axis along the [100] direction. We compare these results with results from probing the magnetotransport properties of the conducting surface states on the [111] facet of FeSi. We also find evidence of 3D variable-range hopping conduction at the bulk-to-surface crossover, extending below 1K, which implies that the electrical transport at the surface of these materials is carried by a thin 3D conducting layer. This 3D surface conduction channel is inconsistent with the lower dimensional states expected for a 3D topological insulator. In conjunction with the magnetic correlations found surface magnetotransport, we also attempt to probe the surface magnetic susceptibility of FeSb2 as well as the evolution of this magnetotransport anisotropy into the bulk of the material as we introduce magnetic order into the bulk of FeSb2 with chemical substitution. 

Advisor: Johnpierre Paglione