Cross-cultural and tribal-centred politics in American Indian studies: assessing a current split in American Indian literary scholarship and re-interpreting Leslie Marmon Silko's Ceremony and Louise Erdrich's Tracks

The thesis examines the current split in American Indian literary studies between cross-cultural and tribal-centred schools of criticism through analyses of Arnold Krupat's, Louis Owens's and Gerald Vizenor's scholarship, on one side, and Elizabeth Cook-Lynn's and Craig Womack's critical work, on the other. The conflicting critical positions, despite their growing importance, have not received a consistent analysis in the critical discourse. The implications of this controversy for the future of American Indian studies and for the ways in which American Indian literature may be studied and taught have not been examined in depth. Particularly, there is little recognition of the validity of tribal-centred contributions to the field. The research seeks to address such gaps in the current scholarship: it develops a synoptic discussion of the opposing critical positions, assesses their strengths and drawbacks, and proposes a possible resolution of the controversy. The thesis argues that crosscultural scholarship (in conjunction with postcolonial and postmodern theory) has contributed importantly to the understanding of discursive hybridity as a vital aspect of American Indian existence, writing and anticolonial resistance. Yet, cross-cultural criticism has sidelined questions regarding tribal sovereignty discourse and tribal centred identity politics. Tribal-centred scholarship is making an important, and still ignored and misunderstood contribution to American Indian studies because it assists the understanding of these two important categories in American Indian experience and decolonisation. Assessing contributions and omissions of either critical position, the research posits that the current critical split could and should be negotiated to enable a more accurate and comprehensive reading of the political discourses that shape American Indian experience, anticolonial struggles and writing. The research illustrates the controversy and its potential mediation through a re-interpretation of two "representative" American Indian novels: Leslie Marmon Silko's Ceremony and Louise Erdrich's Tracks. Part One of the research - chapters one, two and three - analyses the debate, while Part Two - chapters four and five - re-reads Ceremony and Tracks

Oxygen vacancies tuned carrier localization, magnetic and thermoelectric properties in ultrathin (LaNiO3−δ_{3-\delta})1_1/(LaAlO3_{3})1_1(001) superlattices

Here we explore the effect of oxygen vacancies on electronic, magnetic, and thermoelectric properties in ultrathin (LaNiO$_{3-\delta}$)$_1$/(LaAlO$_{3}$)$_1$(001) superlattices (SLs) using a combination of density functional theory calculations including an on-site Coulomb repulsion term (DFT+$U$) and Boltzmann transport theory within the constant relaxation time approximation. For pristine SLs, we find the stabilization of an antiferromagnetic charge-disproportionated (AFM-CD) ($d^{8}${$\underline L$}$^{2}$)$_{S=0}$($d^{8}$)$_{S=1}$ phase, irrespective of strain. At $\delta$ = 0.125 and 0.25, the interplay of confinement and strain triggers a varying degree of charge disproportionation, resulting in ferrimagnetic insulators. However at $\delta$ = 0.5, an insulating phase emerges with alternating stripes of Ni$^{2+}$ (high-spin) and Ni$^{2+}$ (low-spin) and oxygen vacancies ordered along the [110] direction (S-AFM), resulting in a robust $n$-type in-plane power factor of 12.4~$\mu$W/K$^2$ cm (assuming relaxation time $\tau = 4$~fs), at 300~K. This demonstrates the fine tunability of electronic, magnetic, and thermoelectric properties by oxygen vacancies in ultrathin nickelate superlattices.Comment: 7 pages, 3 figure

Confinement-induced metal-to-insulator transition in strained LaNiO3_3/LaAlO3_3 superlattices

Using density functional theory calculations including a Hubbard $U$ term we explore the effect of strain and confinement on the electronic ground state of superlattices containing the band insulator LaAlO$_3$ and the correlated metal LaNiO$_3$. Besides a suppression of holes at the apical oxygen, a central feature is the asymmetric response to strain in single unit cell superlattices: For tensile strain a band gap opens due to charge disproportionation at the Ni sites with two distinct magnetic moments of 1.45$\mu_{\rm B}$ and 0.71$\mu_{\rm B}$. Under compressive stain, charge disproportionation is nearly quenched and the band gap collapses due to overlap of $d_{3z^2-r^2}$ bands through a semimetallic state. This asymmetry in the electronic behavior is associated with the difference in octahedral distortions and rotations under tensile and compressive strain. The ligand hole density and the metallic state are quickly restored with increasing thickness of the (LaAlO$_3$)$_n$/(LaNiO$_3$)$_n$ superlattice from $n=1$ to $n=3$.Comment: 7 pages, 10 Figure