Tunable Rashba spin-orbit interaction at oxide interfaces

The quasi-two-dimensional electron gas found at the LaAlO3/SrTiO3 interface offers exciting new functionalities, such as tunable superconductivity, and has been proposed as a new nanoelectronics fabrication platform. Here we lay out a new example of an electronic property arising from the interfacial breaking of inversion symmetry, namely a large Rashba spin-orbit interaction, whose magnitude can be modulated by the application of an external electric field. By means of magnetotransport experiments we explore the evolution of the spin-orbit coupling across the phase diagram of the system. We uncover a steep rise in Rashba interaction occurring around the doping level where a quantum critical point separates the insulating and superconducting ground states of the system

Influence of non-magnetic impurities on hole doped two-leg Cu-O Hubbard ladders

We study the influence of non magnetic impurities on the phase diagram of doped two-leg Hubbard Cu-O ladders. In the absence of impurities this system posseses d-wave superconducting states and orbital current states depending on the doping. A single, strong, scatterer modifies its environment locally and this effect is assessed using a renormalization group analysis. At high doping, disorder causes intraband instabilities and at low doping it promotes interband instabilities. In the former case, we extend the boundary conformal field theory method, developed in the context of single chains, to handle the ladder problem, and we find exact closed-form analytical expressions for the correlation functions. This allows us to compute experimentally measurable local quantities such as the nuclear magnetic resonance line broadenings and scanning tunnelling microscope profiles. We also discuss the low doping regime where Kondo physics is at play, making qualitative predictions about its nature. Insight into collective effects is also given in the many weak impurities case, based on an RG approach. In this regime, one sees the interplay between interactions and disorder. We emphasize the influence of the O atoms on disorder effects both for the single- and for the many-defect situations.Comment: accepted to be published in NJP special editio

Band inversion driven by electronic correlations at the (111) LaAlO3_3/SrTiO3_3 interface

Quantum confinement at complex oxide interfaces establishes an intricate hierarchy of the strongly correlated $d$-orbitals which is widely recognized as a source of emergent physics. The most prominent example is the (001) LaAlO$_3$/SrTiO$_3$(LAO/STO) interface, which features a dome-shaped phase diagram of superconducting critical temperature and spin-orbit coupling (SOC) as a function of electrostatic doping, arising from a selective occupancy of $t_{2g}$ orbitals of different character. Here we study (111)-oriented LAO/STO interfaces - where the three $t_{2g}$ orbitals contribute equally to the sub-band states caused by confinement - and investigate the impact of this unique feature on electronic transport. We show that transport occurs through two sets of electron-like sub-bands, and the carrier density of one of the sets shows a non-monotonic dependence on the sample conductance. Using tight-binding modeling, we demonstrate that this behavior stems from a band inversion driven by on-site Coulomb interactions. The balanced contribution of all $t_{2g}$ orbitals to electronic transport is shown to result in strong SOC with reduced electrostatic modulation.Comment: 5 pages, 4 figures, (+ supplemental material

Reducing Sexual Risk among Racial/ethnic-minority Ninth Grade Students: Using Intervention Mapping to Modify an Evidenced-based Curriculum

Background: Racial/ethnic-minority 9th graders are at increased risk for teen pregnancy, HIV, and STIs compared to their White peers. Yet, few effective sexual health education programs exist for this population. Purpose: To apply IM Adapt—a systematic theory- and evidence-based approach to program adaptation—to modify an effective middle school sexual health education curriculum, It’s Your Game…Keep It Real! (IYG), for racial/ethnic-minority 9th graders. Methods: Following the six steps of IM Adapt, we conducted a needs assessment to describe the health problems and risk behaviors of the new population; reviewed existing evidence-based programs; assessed the fit of IYG for the new population regarding behavioral outcomes, determinants, change methods, delivery, and implementation; modified materials and activities; planned for implementation and evaluation. Results: Needs assessment findings indicated that IYG targeted relevant health and risk behaviors for racial/ethnic-minority 9th graders but required additional focus on contraceptive use, dating violence prevention, active consent, and access to healthcare services. Behavioral outcomes and matrices of change objectives for IYG were modified accordingly. Theoretical methods and practical applications were identified to address these behavioral outcomes, and new activities developed. Youth provided input on activity modifications. School personnel guided modifications to IYG’s scope and sequence, and delivery. The adapted program, Your Game, Your Life, comprised fifteen 30-minute lessons targeting determinants of sexual behavior and healthy dating relationships. Pilot-test data from 9th graders in two urban high schools indicate promising results. Conclusion: IM Adapt provides a systematic theory- and evidence-based approach for adapting existing evidence-based sexual health education curricula for a new population whilst retaining essential elements that made the original program effective. Youth and school personnel input ensured that the adapted program was age-appropriate, culturally sensitive, and responsive to the needs of the new population. IM Adapt contributes to the limited literature on systematic approaches to program adaptation

Unique Changes in Mitochondrial Genomes Associated with Reversions of S-Type Cytoplasmic Male Sterility in Maizemar

Cytoplasmic male sterility (CMS) in plants is usually associated with the expression of specific chimeric regions within rearranged mitochondrial genomes. Maize CMS-S plants express high amounts of a 1.6-kb mitochondrial RNA during microspore maturation, which is associated with the observed pollen abortion. This transcript carries two chimeric open reading frames, orf355 and orf77, both unique to CMS-S. CMS-S mitochondria also contain free linear DNA plasmids bearing terminal inverted repeats (TIRs). These TIRs recombine with TIR-homologous sequences that precede orf355/orf77 within the main mitochondrial genome to produce linear ends. Transcription of the 1.6-kb RNA is initiated from a promoter within the TIRs only when they are at linear ends. Reversions of CMS-S to fertility occur in certain nuclear backgrounds and are usually associated with loss of the S plasmids and/or the sterility-associated region. We describe an unusual set of independently recovered revertants from a single maternal lineage that retain both the S plasmids and an intact orf355/orf77 region but which do not produce the 1.6-kb RNA. A 7.3-kb inversion resulting from illegitmate recombination between 14-bp microrepeats has separated the genomic TIR sequences from the CMS-associated region. Although RNAs containing orf355/orf77 can still be detected in the revertants, they are not highly expressed during pollen development and they are no longer initiated from the TIR promoter at a protein-stabilized linear end. They appear instead to be co-transcribed with cytochrome oxidase subunit 2. The 7.3-kb inversion was not detected in CMS-S or in other fertile revertants. Therefore, this inversion appears to be a de novo mutation that has continued to sort out within a single maternal lineage, giving rise to fertile progeny in successive generations

Smecticlike phase for modulated XY spins in two dimensions

The row model for frustrated XY spins on a triangular lattice in 2D is used to study incommensurate{IC}) spiral and commensurate{C} antiferromagnetic (AF) phases, in the regime where a C-IC transition occurs. Using fluctuating boundary conditions and specific histogram techniques, a detailed Monte Carlo (MC) study reveals more structure in the phase diagram than found in previous MC simulations of the full parameter space. On the (C) side, equilibrium configurations consist of alternating stripes of spiral phases of opposite chirality separated by walls of the (C) phase. For this same parameter regime, thermodynamic quantities are computed analytically using the NSCHA, a generalization of the self consistent harmonic approximation appropriate for chiral systems. On the commensurate side of the (C)-(IC) boundary, NSCHA predicts an instability of the (C) phase. This suggests that the state is spatially inhomogeneous, consistent with the present MC result: it resembles the smectic-A phase of liquid crystals, and its existence implies that the Lifshitz point is at ${T=0}$ for modulated XY spins in 2D. The connection between frustrated XY systems and the vortex state of strong type II superconductors suggests that the smectic phase may correspond to a vortex liquid phase of superconducting layers.Comment: Single Postscript file containing 24 pages of text and 8 figures. To appear in May 1 issue of Phys. Rev. B, Vol. 5

Platform of Citizen Interaction: the contribution to the governability of New TIC´s and Citizen Relational Management

Understanding "governability" as an interaction process among government and society, the New Technologies of Information and Communications (NTICs) can contribute as a strategy of improvement and conversion in the type of communication between both actors. This article introduces concepts referred to Customer Relationship Management applications turned into Citizen Relationship Management tools. The plus of a modeling of the multiplatforms functionalities that this solution offers and a protocol of implementation and system migration is a step forward in the achievement of obtaining an electronic government with civil democratic interaction and transparency in the management. The idea of a Platform of Citizen Interaction that auspice as a repository of the communication between public and civil entities allows having a unique and centralized database capable of being segmented of different ways to attend to a great diversity of subject matters.VIII Workshop Innovación en Sistemas de Software (WISS).Red de Universidades con Carreras en Informática (RedUNCI

Platform of Citizen Interaction: the contribution to the governability of New TIC´s and Citizen Relational Management

Understanding "governability" as an interaction process among government and society, the New Technologies of Information and Communications (NTICs) can contribute as a strategy of improvement and conversion in the type of communication between both actors. This article introduces concepts referred to Customer Relationship Management applications turned into Citizen Relationship Management tools. The plus of a modeling of the multiplatforms functionalities that this solution offers and a protocol of implementation and system migration is a step forward in the achievement of obtaining an electronic government with civil democratic interaction and transparency in the management. The idea of a Platform of Citizen Interaction that auspice as a repository of the communication between public and civil entities allows having a unique and centralized database capable of being segmented of different ways to attend to a great diversity of subject matters.VIII Workshop Innovación en Sistemas de Software (WISS).Red de Universidades con Carreras en Informática (RedUNCI

Ordering in a spin glass under applied magnetic field

Torque, torque relaxation, and magnetization measurements on a AuFe spin glass sample are reported. The experiments carried out up to 7 T show a transverse irreversibility line in the (H,T) plane up to high applied fields, and a distinct strong longitudinal irreversibility line at lower fields. The data demonstrate for that this type of sample, a Heisenberg spin glass with moderately strong anisotropy, the spin glass ordered state survives under high applied fields in contrast to predictions of certain "droplet" type scaling models. The overall phase diagram closely ressembles those of mean field or chiral models, which both have replica symmetry breaking transitions.Comment: 4 pages, 3 figures, accepted for PR