Ag and Au Atoms Intercalated in Bilayer Heterostructures of Transition Metal Dichalcogenides and Graphene

The diffusive motion of metal nanoparticles Au and Ag on monolayer and between bilayer heterostructures of transition metal dichalcogenides and graphene are investigated in the framework of density functional theory. We found that the minimum energy barriers for diffusion and the possibility of cluster formation depend strongly on both the type of nanoparticle and the type of monolayers and bilayers. Moreover, the tendency to form clusters of Ag and Au can be tuned by creating various bilayers. Tunability of the diffusion characteristics of adatoms in van der Waals heterostructures holds promise for controllable growth of nanostructures.Comment: accepted, APL Ma

Quantum Transport Characteristics of Lateral pn-Junction of Single Layer TiS3

Using density functional theory and nonequilibrium Greens functions-based methods we investigated the electronic and transport properties of monolayer TiS3 pn-junction. We constructed a lateral pn-junction in monolayer TiS3 by using Li and F adatoms. An applied bias voltage caused significant variability in the electronic and transport properties of the TiS3 pn-junction. In addition, spin dependent current-voltage characteristics of the constructed TiS3 pn-junction were analyzed. Important device characteristics were found such as negative differential resistance and rectifying diode behaviors for spin-polarized currents in the TiS3 pn-junction. These prominent conduction properties of TiS3 pn-junction offer remarkable opportunities for the design of nanoelectronic devices based on a recently synthesized single-layered material

LOCAL CULTURE EXPERIENCE AND NOVELTY SEEKING: A COMPARISON ON ISTANBUL AND ANTALYA TOURISM DESTINATIONS

Distinguishing the society from others, cultural assets create a unique local culture experience for tourists and lead to satisfaction by influencing the novelty seeking motivation. Based on this hypothesis, the aims of this research are as follows; a) to examine the effect of the local cultural experience on novelty seeking behavior, b) to examine the influence of the local culture experience on tourist satisfaction, and c) to assess the mediating role of novelty seeking between local cultural experience and satisfaction. Using structural equation modeling, a comparative study was carried out on Turkey's most-tourist attracting destinations which have distinctive DNA's in accordance with their specific positioning strategies. Findings revealed that local culture experience, novelty seeking and tourist satisfaction variables are associated with each other in both destinations. The SEM suggests that the novelty seeking variable have the mediating role between local culture experience and satisfaction.&nbsp

Enhancing response time thresholds with response behaviors for detecting disengaged examinees

The item responses of examinees who rapid-guess, who do not spend enough time reading and engaging with an item, will not reflect their true ability on that item. Rapid-disengagement refers to rapidly selecting a response to multiple-choice items (i.e., rapid-guess), omitting items, or providing short-unrelated answers to open-ended items in an unreasonably short time. Such rapid responses need to be identified to enhance the validity of the arguments from the test data. Detection of rapid-guessing behaviors is typically based on identifying a threshold to represent the minimum response time required for the student to have thoughtfully considered a given item. This study investigates whether using response behaviors can improve the detection of rapid-disengagement by investigating two approaches: (a) using response behaviors to decide on the size of the threshold, and (b) using response behaviors as a condition for detecting disengaged examinees in addition to response times, referred as enhanced methods. Process data and item responses from the PISA 2012 computer-based mathematics assessment were used to examine both approaches under threshold values varying from very small (5 s) to very large (60 s). Results suggested that response behaviors can provide meaningful input on establishing the size of the threshold and that while enhanced methods performed better than using only response times in recognizing rapid-disengagement in some cases, no clear pattern was observed as to when such improvement occurs. This study makes a unique contribution by inspecting the response behaviors of disengaged examinees and providing guidelines on using response behaviors to decide on the size of the threshold. This study suggests response behavior categories that can be applicable to many item and response types, which make them suitable for use in digitally-based large-scale assessments

Phonon Softening and Direct to Indirect Bandgap Crossover in Strained Single Layer MoSe2

Motivated by recent experimental observations of Tongay et al. [Tongay et al., Nano Letters, 12(11), 5576 (2012)] we show how the electronic properties and Raman characteristics of single layer MoSe2 are affected by elastic biaxial strain. We found that with increasing strain: (1) the E' and E" Raman peaks (E1g and E2g in bulk) exhibit significant red shifts (up to 30 cm-1), (2) the position of the A1' peak remains at 180 cm-1 (A1g in bulk) and does not change considerably with further strain, (3) the dispersion of low energy flexural phonons crosses over from quadratic to linear and (4) the electronic band structure undergoes a direct to indirect bandgap crossover under 3% biaxial tensile strain. Thus the application of strain appears to be a promising approach for a rapid and reversible tuning of the electronic, vibrational and optical properties of single layer MoSe2 and similar MX2 dichalcogenides.Comment: http://link.aps.org/doi/10.1103/PhysRevB.87.12541