Seeing and manipulating spin-spin interactions at the single atomic level

Mathematical and Physical Sciences: 2nd Place (The Ohio State University Edward F. Hayes Graduate Research Forum)The 2007 Nobel prize in physics went to Albert Fert and Peter Grünberg “for the discovery of Giant Magnetoresistance (GMR)” which is an effect that underlies all of the read sensors in today’s hard disk drives. These initial studies of GMR have opened a new paradigm for future electronics called ‘spintronics’. In contrast to conventional charge-based electronics, spintronics relies on the electron’s spin, which is a fundamental magnetic moment that has two energy states, spin-up or spin-down, analogous to the 1 or 0 states of a bit in a computer. One key challenge for the realization of spintronics is the development of ferromagnetic semiconductors which could potentially combine magnetic recording and digital logic in a single device. One promising candidate is GaMnAs, in which nonmagnetic GaAs can be made ferromagnetic by introducing only a few percent of Mn. The low ferromagnetic transition temperature (currently Tc<-100C) of GaMnAs, prevents use in practical devices which operate at room temperature. A better understanding of GaMnAs at a microscopic level is necessary to probe the limits of Tc in this material. We have built a low temperature (-260C) ultrahigh vacuum scanning tunneling microscope (STM) to study spin-spin interactions in GaMnAs at the atomic level. Our STM can be used to image semiconductor surfaces with atomic resolution, manipulate individual Mn atoms, and spectroscopically probe Mn-Mn interactions. A clean GaAs surface is prepared by cleaving a p-type GaAs crystal inside the ultrahigh vacuum chamber. A low coverage of Mn atoms is then evaporated onto the surface. To more closely mimic a bulk-like environment, single Mn atoms can be substituted for Ga in the first layer of the surface, by applying a voltage pulse with the STM tip. To study Mn-Mn interactions, we make pairs of substituted Mn. Our STM studies on Mn pairs show interesting spin-spin interactions which strongly depend on the Mn separation and relative crystal orientation. For example, coupling between two Mn atoms switches from ferromagnetic (parallel spins) to antiferromagnetic (antiparallel spins) depending on the pair’s orientation. We are also developing a capability for spin-polarized STM to better study long range magnetic ordering between pairs and larger clusters of substituted Mn. By using a magnetic STM tip such as Ni or Cr, spin-polarized STM can selectively detect different spin states of Mn clusters. These studies will contribute to a microscopic understanding of the underlying physics of GaMnAs, and will help in the search for new semiconductor materials which exhibit ferromagnetism above room temperature.No embarg

Counselors\u27 self-discrepancy and its impact on their burnout and wellness

This study explores the relationships between counselors’ professional, personal, and reflected selves as well as between counselors’ self-discrepancies and their burnout and wellness. Moreover, an investigation on the impacts of counselors’ self-discrepancies on their burnout and wellness as a professional was conducted. The use of self has been emphasized in order for counselors to elicit meaningful outcome with clients. To demonstrate the use of self as an instrument of the counseling process, integrating professional, personal, and reflected selves is necessary for counselors. One hundred ninety five (N = 195) professional counselors in Mid-South States, who currently practice, supervise, educate, or are in charge of counseling-related work, as well as those who temporarily ceased their career participated in this study. Results of testing for the relationship between counselors’ professional, personal, and reflected selves found that there were significant positive correlations among the three selves. Moreover, results of testing for relationship between counselors’ self-discrepancies and their burnout and wellness indicated that all three discrepancies between their professional, personal, and reflected selves were positively related to the level of burnout and negatively related to the level of wellness. Additionally, multiple regression analysis revealed that counselors’ professional- personal self-discrepancy positively predicted the level of burnout while negatively predicting the level of wellness. However, counselors’ self-discrepancy between professional and reflected selves, as well as personal selves and reflected selves, were unable to significantly predict both the level of their burnout or wellness

STRATEGIC KNOWLEDGE DISCLOSURE: ITS EFFECT ON COMPETITIVE RESPONSE AND KNOWLEDGE-BASED COMPETENCIES IN THE GLOBAL HARD DISK DRIVE INDUSTRY

How does a leading firm sustain its competence-based advantage in a competitive landscape against threats of imitation and substitution? In high-velocity competitive markets, an inherent tension arises when firms wish to prolong the value of their technological competencies, while rivals seek to make those competencies obsolete. These markets are characterized by continuous technological change, fickle customers, and frequent shifts in the competitive landscape. Firms must continually update their innovative competencies that are recurrently targets of imitation and substitution, and managers face challenges in discerning the appropriate competencies their firms should commit to and which they should avoid, resulting in the difficulty of setting straightforward strategic goals for the firm. Looking in the hard disk drive industry from 1987 to 1999, I empirically show that leading firms' knowledge disclosure of core technologies has a positive effect on the probability of laggards imitating the leader. Moreover, I show that after leading firms disclose, they introduce next-generation products sooner and prevent laggards from quickly introducing their next-generation products. Thus, I suggest that a leading firm's knowledge disclosing activities can shape the competitive landscape by influencing rivals' scope of search for innovation opportunities. Namely, leading firms can prolong their established competencies by disclosing knowledge on their innovations by promoting imitation and delaying or preventing substitution

Atomic Scale Magnetic Sensing and Imaging Based on Diamond NV Centers

The development of magnetic sensors simultaneously satisfying high magnetic sensitivity and high spatial resolution becomes more important in a wide range of fields including solid-state physics and life science. The nitrogen-vacancy (NV) center in diamond is a promising candidate to realize nanometer-scale magnetometry due to its excellent spin coherence properties, magnetic field sensitivity, atomic-scale size and versatile operation condition. Recent experiments successfully demonstrate the use of NV center in various sensing and imaging applications. In this chapter, we review the basic sensing mechanisms of the NV center and introduce imaging applications based on scanning magnetometry and wide field-of-view optics

P5: Plug-and-Play Persona Prompting for Personalized Response Selection

The use of persona-grounded retrieval-based chatbots is crucial for personalized conversations, but there are several challenges that need to be addressed. 1) In general, collecting persona-grounded corpus is very expensive. 2) The chatbot system does not always respond in consideration of persona at real applications. To address these challenges, we propose a plug-and-play persona prompting method. Our system can function as a standard open-domain chatbot if persona information is not available. We demonstrate that this approach performs well in the zero-shot setting, which reduces the dependence on persona-ground training data. This makes it easier to expand the system to other languages without the need to build a persona-grounded corpus. Additionally, our model can be fine-tuned for even better performance. In our experiments, the zero-shot model improved the standard model by 7.71 and 1.04 points in the original persona and revised persona, respectively. The fine-tuned model improved the previous state-of-the-art system by 1.95 and 3.39 points in the original persona and revised persona, respectively. To the best of our knowledge, this is the first attempt to solve the problem of personalized response selection using prompt sequences. Our code is available on github~\footnote{https://github.com/rungjoo/plug-and-play-prompt-persona}.Comment: EMNLP 2023 main conferenc

Internalized Model Minority Myth, Asian Values, and Help-Seeking Attitudes among Asian American Students

The present study examined cultural factors underlying help-seeking attitudes of Asian American college students (N = 106). Specifically, we explored internalized model minority myth as a predictor of help-seeking attitudes and tested an intrapersonal-interpersonal framework of Asian values as a mechanism by which the two are related. Results indicated that internalized model minority myth significantly predicted unfavorable help-seeking attitudes, and emotional self-control mediated this relationship. Interpersonal values and humility were nonsignificant mediators, contrary to our hypotheses. The findings suggest that the investigation of internalized model minority myth in help-seeking research is a worthwhile endeavor, and they also highlight emotional self-control as an important explanatory variable in help-seeking attitudes of Asian American college students

Culturally Responsive Distance Counselor Education for International Counseling Students

Counselor education programs have increasingly offered distance education during the last decades. As one of the growing student populations in counselor education programs, international students need to be given more attention pertaining to their cultural and educational experiences as counseling students. Although distance learning in counselor education has gained empirical support for its effectiveness, it may still pose challenges to international counseling students due to their unique characteristics such as language barriers and cultural differences, which may render differing qualities of students’ learning experiences. Aiming to enhance our understanding of this student population to provide culturally responsive distance counselor education, the present article introduces international students in the context of distance counselor education and discusses implications for supporting international students in distance counselor education

Dynamics of Online Engagement: Counseling Students’ Experiences and Perceptions in Distance Learning

In this article, the authors present counseling students’ personal accounts of their experiences in distance education with a focus on online engagement based on an extensive review of the counseling literature. In addition, an evaluation tool was introduced for gathering qualitative and quantitative information regarding patterns of instructor engagement efforts and styles. Facilitating factors for experiential online learning were also identified from the students’ perceptions of online learning experience. Finally, the results were used to make specific recommendations for counselor educators to enhance their teaching efficacy and engagement