First-principles study of the electronic structure and magnetism of CaIrO3_3

I study the electronic structure and magnetism of postperovskite CaIrO$_3$ using first-principles calculations. The density functional calculations within the local density approximation without the combined effect of spin-orbit coupling and on-site Coulomb repulsion show the system to be metallic, which is in disagreement with the recent experimental evidences that show CaIrO$_3$ to be an antiferromagnetic Mott insulator in the $J_\textrm{eff}$ = 1/2 state. However, when spin-orbit coupling is taken into account, the Ir $t_{2g}$ bands split into fully filled $J_\textrm{eff}$ = 3/2 bands and half-filled $J_\textrm{eff}$ = 1/2 bands. I find that spin-orbit coupling along with a modest on-site Coulomb repulsion opens a gap leading to a Mott insulating state. The ordering is antiferromagnetic along the c axis with total moments aligned antiparallel along the c axis and canted along the b axis.Comment: Updated the text and figures to reflect the published versio

Strong-coupling electron-phonon superconductivity in noncentrosymmetric quasi-one-dimensional K2_2Cr3_3As3_3

I study the lattice dynamics and electron-phonon coupling in non-centrosymmetric quasi-one-dimensional K$_2$Cr$_3$As$_3$ using density functional theory based first principles calculations. The phonon dispersions show stable phonons without any soft-mode behavior. They also exhibit features that point to a strong interaction of K atoms with the lattice. I find that the calculated Eliashberg spectral function shows a large enhancement around 50 cm$^{-1}$. The phonon modes that show large coupling involve in-plane motions of all three species of atoms. The $\mathbf{q}$ dependent electron-phonon coupling decreases strongly away from the $q_z = 0$ plane. The total electron-phonon coupling is large with a value of $\lambda_{\textrm{ep}} = 3.0$, which readily explains the experimentally observed large mass enhancement

Research, Creative Works, and Commercialization at UAA FY15 through FY16 YTD.

The UAA Research and Commercialization trend is upward. UAA is experiencing significant growth in research, creative works, and commercialization. We are pursuing a strategic approach to fostering, supporting, and expanding faculty and student research efforts and commercialization by creating a climate of innovation and collaboration

A Prospectus on Substantive Change

Prepared for The Commission on Colleges, Northwest Association of Schools and Colleges, October 1, 1987. For consideration by the Commission on Colleges at its December 5 and 6, 1987, meeting at the Salt Lake Hilton Hotel

Sex Offender Treatment Program: Preliminary Description

This report provides a summary of the history of sex offender treatment in Alaska, including the current status of treatment programs offered by the Alaska Department of Corrections, a review of literature on sex offender treatment and recidivism issues, and a summary of the descriptive characteristics of individuals who came in contact with the Hiland Mountain Correctional Center from January 1987 to March 1993.Alaska Department of CorrectionsIntroduction / Sex Offender Treatment in Alaska / Literature Review / Methodology / Results / Conclusion and Recommendations / Bibliograph

Alaska Public Safety Statewide Survey: Component Two of Alaska Public Safety Project

Results of a statewide public opinion survey indicate that, contrary to the commonly portrayed perspective, anxiety about crime in Alaska is not particularly high. Moreover, many residents feel that crime levels in their communities have stayed the same or are actually decreasing. Over 600 Alaska residents in five regions throughout the state (Anchorage, Fairbanks, Southeast, Valdez/Kenai/Mat-Su, and rural Alaska) were surveyed by telephone for this study.Alaska Department of Public SafetyAcknowledgements / Introduction / Demographic Profiles of Survey Respondents / Quality of Life / Community Problems / Perceived Magnitude of Common Public Safety Problems / Priorities for Police Response to Problems / Alaskan's Willingness to Become Involved in Police Efforts / Crime Trends, Sense of Safety, and Worry About Violent Crime / Drugs and Alcohol: Relationship to Crime, Magnitude of Problems, and Risks / Drugs and Alcohol: Personal Knowledge of Users of Alcohol and Drugs and Sellers of Drugs / Combatting Illegal Drug Use and Abuse / Criminal Victimization, Reporting, and Satisfaction with Police / Various Opinion Statements / Conclusion / Appendix A. Methodology / Appendix B. Distribution of Interviews / Appendix C. Questionnair

Proposal for ultrafast switching of ferroelectrics using mid-infrared pulses

I propose a method for ultrafast switching of ferroelectric polarization using mid-infrared pulses. This involves selectively exciting the highest frequency $A_1$ phonon mode of a ferroelectric material with an intense mid-infrared pulse. Large amplitude oscillations of this mode provides a unidirectional force to the lattice such that it displaces along the lowest frequency $A_1$ phonon mode coordinate because of a nonlinear coupling of the type $g Q_{\textrm{P}} Q_{\textrm{IR}}^2$ between the two modes. First principles calculations show that this coupling is large in transition-metal oxide ferroelectrics, and the sign of the coupling is such that the lattice displaces in the switching direction. Furthermore, I find that the lowest frequency $A_1$ mode has a large $Q_{\textrm{P}}^3$ order anharmonicity, which causes a discontinuous switch of electric polarization as the pump amplitude is continuously increased

Theory of nonlinear phononics for coherent light-control of solids

We present a microscopic theory for ultrafast control of solids with high-intensity terahertz frequency optical pulses. When resonant with selected infrared-active vibrations, these pulses transiently modify the crystal structure and lead to new collective electronic properties. The theory predicts the dynamical path taken by the crystal lattice using first-principles calculations of the energy surface and classical equations of motion, as well as symmetry considerations. Two classes of dynamics are identified. In the perturbative regime, displacements along the normal mode coordinate of symmetry-preserving Raman active modes can be achieved by cubic anharmonicities. This explains the light-induced insulator-to-metal transition reported experimentally in manganites. We predict a regime in which ultrafast instabilities that break crystal symmetry can be induced. This nonperturbative effect involves a quartic anharmonic coupling and occurs above a critical threshold, below which the nonlinear dynamics of the driven mode displays softening and dynamical stabilization.Comment: updated to reflect the published versio

The Strength of Association: Population Density and Social Deviance

This issue is the second of three in Series 3a, "The Strength of Community-level Rates of Association," mapping Anchorage neighborhood characteristics by census block area, highlighting the correlation or lack of correlation between those characteristics and the level of crime and social deviance in the neighborhood as measured by police calls for service for six types of offenses. Maps in this subseries should be compared with the maps in Series 3b, "An Examination of Police Service Deployment (Police Calls for Service)," for a full picture of the "strength of association."This issue of Anchorage Community Indicators provides a brief examination of the relationship between population density and social deviance in the Municipality of Anchorage. A commonly held belief is that social density is positively correlated with social deviance, despite only sparse scientific evidence in support of this theory. A previous issue of Anchorage Community Indicators ("The Strength of Association: Housing Density and Delinquency," ACI 3a(1) (Jul 2004)) found no evidence of a relationship between housing density and deviance. The current issue builds on these previously reported findings by introducing a second measure of social density: population density, once again finding no evidence that social density of Anchorage neighborhoods is associated with community-level rates of social deviance