Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Thesis_ASKumar.pdf (22.81 MB)

ETD Abstract Container

Abstract Header

Investigating Electron-Electron Interactions in 2D Semiconductor Systems through Quantum Transport

Kumar, Arvind Shankar Shankar
http://rave.ohiolink.edu/etdc/view?acc_num=case1624475904980951

Abstract Details

2021, Doctor of Philosophy, Case Western Reserve University, Physics.
Electron-electron interactions (EEIs) are one of the few unsolved mysteries in condensed matter physics. When these interactions are strong enough, they can lead to fascinating physics like high-Tc superconductivity, Wigner solids and many other exotic quantum phases for which there is no complete theoretical description. Fermi Liquid (FL) theory, which has emerged as the pre-eminent theory for describing EEIs, fails in these cases where interactions are strong. However, the limits of the validity of Fermi Liquid theory in an interacting electronic system has not yet been experimentally tested in a systematic way. 2D electron/hole systems (2DES/2DHS) are an ideal system for this purpose due to the wide tunability of EEI strength through changing carrier density, and the clear signatures of EEIs in 2D magneto-transport. In this thesis, we first explore magneto-transport signatures of EEIs for a weakly interacting 2DES in van der Waals (vdW) layered semiconductor InSe. We analyse these in the framework of FL theory and extract the FL parameter which quantifies electron spin-exchange interaction strength. Next, we investigate similar magneto-transport signatures of EEIs observed in a strongly interacting 2DHS in a GaAs/AlGaAs heterostructure over the temperature range 0.1-1 K. We find that, in this case, the conventional perturbative approach of treating EEIs in FL theory does not account for transport behavior in this system. We further find a resolution of this fact at higher temperatures within the range of study through the observed signatures of collective viscous transport of the 2D hole fluid, thus lending a direction to fully understand transport behavior in this strongly correlated regime. Finally, we explore the possiblity of building new nanostructures for 2D transport, by investigating the transport properties of a vdW semiconductor heterostructure InSe/GaSe. We find that this heterostructure has interesting properties like large gate-transfer hysteresis and a time-dependent conductance decay, which can be explained by considering the gate electric field induced interfacial charge transfer from InSe to GaSe enforced by the band alignment between InSe and GaSe. This work highlights important effects to consider while building new heterostructure systems to explore interesting physics and build novel devices. Overall, this thesis explores EEI effects in 2DES/2DHS over a wide range of carrier densities and in different material systems, and provides a direction for understanding these effects in the strongly correlated regime, and proposes a direction to discover new systems to explore such effects.
Xuan Gao, Prof. (Advisor)
Walter Lambrecht, Prof. (Committee Member)
Harsh Mathur, Prof. (Committee Member)
Lei Zhu, Prof. (Committee Member)
129 p.
Condensed Matter Physics; Physics

Recommended Citations

Citations

  • Kumar, A. S. S. (2021). Investigating Electron-Electron Interactions in 2D Semiconductor Systems through Quantum Transport [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1624475904980951

    APA Style (7th edition)

  • Kumar, Arvind Shankar. Investigating Electron-Electron Interactions in 2D Semiconductor Systems through Quantum Transport. 2021. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1624475904980951.

    MLA Style (8th edition)

  • Kumar, Arvind Shankar. "Investigating Electron-Electron Interactions in 2D Semiconductor Systems through Quantum Transport." Doctoral dissertation, Case Western Reserve University, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=case1624475904980951

    Chicago Manual of Style (17th edition)

case1624475904980951
66
© 2021, all rights reserved.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.