Article
Materials Science, Multidisciplinary
Jianhong He, Huazhong Guo, Xiaokai Yue, Jie Gao
Summary: This study reports phase-resolved microwave magnetotransport measurements of a Coulomb-coupled quantum point contact in the edge state regime, revealing significant asymmetry in inductive admittance under reversal of magnetic field while observing field-symmetric conductance. Additionally, fluctuations in asymmetry as a function of magnetic field and transmission were found, providing direct evidence of kinetic effects associated with non-equilibrium polarization charge contributing to dynamical magnetoasymmetry in phase-coherent mesoscopic conductors. Moreover, a striking magnetoasymmetry in electronic transit time was also discovered, offering important insights into Coulomb coupling effects on quantum dynamics of electrons.
Article
Cardiac & Cardiovascular Systems
Aleksandra B. Gruslova, Andrew G. Cabe, Anil Kottam, John Walmsley, John E. Porterfield, Edward Y. Sako, Marc D. Feldman, Jonathan W. Valvano
Summary: This study demonstrated that measuring admittance from chest tubes can detect changes in left ventricular volumes and may have diagnostic value for unexplained hypotension. The method is able to distinguish between blood and muscle components, making it a potentially useful tool for early detection.
ANNALS OF THORACIC SURGERY
(2022)
Article
Optics
Imen Saidi
Summary: The study found that due to polarization effects, the total (linear plus nonlinear) absorption coefficient peak is enhanced and the wavelength is reduced; with increasing indium composition, the peak of the total optical absorption coefficient increases and shows a red shift; by optimizing the concentration of planar doping in the AlInN barriers, the peak of the total absorption coefficient increases and red-shifted or blue-shifted.
Article
Materials Science, Multidisciplinary
Gaoyang Li, Hao Jin, Yadong Wei, Jian Wang
Summary: This article proposes a method to enhance electron-magnon coupling and analyzes it from the perspective of theoretical models and transport. By adjusting the density of states at the interface, the spin conductance can be significantly enhanced, providing a new approach to manipulate electron-magnon coupling.
Article
Chemistry, Physical
Paulo Roberto Bueno, David Alejandro Miranda Mercado
Summary: The quantum rate theory predicts electron transfer rate between quantum states and is crucial for understanding electron transport in electrochemical reactions and molecular electronics. This study demonstrates the relationship between quantum rate theory and relativity theory in graphene, opening possibilities for fabricating quantum devices using inexpensive electrochemical setups. The study introduces a quantum rate model for graphene and highlights its applicability to electron transport in molecular films, providing insights into the best means of conducting electron transport in graphene.
JOURNAL OF PHYSICAL CHEMISTRY C
(2022)
Article
Multidisciplinary Sciences
David A. Kealhofer, Robert Kealhofer, Daniel Ohara, Tyler N. Pardue, Susanne Stemmer
Summary: A thin film of cadmium arsenide can exhibit the characteristics of a three-dimensional topological insulator, with experimental signatures observed through quantum capacitance. By leveraging the flexibility of heterostructures, researchers have demonstrated a method to control the energy of topological surface states in cadmium arsenide, opening up new avenues for engineering topological insulators based on this material.
Article
Physics, Multidisciplinary
Nastaran Dashti, Matteo Acciai, Sara Kheradsoud, Maciej Misiorny, Peter Samuelsson, Janine Splettstoesser
Summary: In this study, the quantum screening effects in voltage- and temperature-biased coherent conductors were explored, and it was demonstrated that an additional ac-driven terminal can act as a probe for directly measuring these effects. The research found that the screening of charges induced by static biases affects the standard linear thermoelectric response coefficients, which can be observed under realistic experimental conditions and controlled by the ac driving.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Y. D. Sun, Lei Wang, Lili Lang, Ke Xia, S. M. Zhou
Summary: We investigated the hysteresis and training effect of spin current in Pt/Y3Fe5O12 heterostructures under successive cycles of ionic liquid gate voltage Vg. The diode-like behaviors of inverse spin Hall effect voltage and spin Hall magnetoresistance in spin pumping during the first half cycle of Vg, as well as the hysteresis in the first cycle of Vg, become weak and disappear in the second cycle due to the training effect. This study provides valuable insights into enhancing the functional performance of electrically controlled spin current devices.
Article
Physics, Applied
Noboru Fukuhara, Fumimasa Horikiri, Taiki Yamamoto, Takenori Osada, Kenji Kasahara, Takayuki Inoue, Takashi Egawa
Summary: By measuring and simulating the capacitance-frequency-voltage and conductance-frequency-frequency-voltage curves of long-gate field-effect transistors with different gate lengths, it is confirmed that the two peaks in the conductance-frequency-frequency curves are caused by the two-dimensional electron gas channel resistance and the gate current leakage. The positions and intensities of the two peaks are quantitatively determined. The effect of acceptor concentration in the GaN channel-layer on the peak position at weak inversion is also discussed.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Electrochemistry
Qingxiao Zhou, Li Wang, Weiwei Ju, Dongtao Su, Juncheng Zhu, Yongliang Yong, Shilin Wu
Summary: The charge storage capacity, quantum capacitance, and atomic structures of transition-metal doped graphene-like/graphene heterostructures were studied using density functional theory (DFT). The impact of transition-metal (TM) doping on the capacitance capacity of different types of heterostructures was also examined. The findings showed that doping was more effective than vacancy defects in enhancing the quantum capacitance of heterostructures. The Sc-doped WSe2/graphene exhibited the highest quantum capacitance (838.24 mu F/cm2), making it a promising material for supercapacitors.
ELECTROCHIMICA ACTA
(2023)
Article
Materials Science, Multidisciplinary
Shawutijiang Sidikejiang, Philipp Henning, Uwe Rossow, Heiko Bremers, Ferdinand Scholz, Andreas Hangleiter
Summary: Semipolar (11 (2) over bar2) AlInN/GaN heterostructures on GaN templates were studied using photoluminescence (PL) spectroscopy at different temperatures. The polarization-resolved PL measurements showed dominant polarization along [11 (2) over bar(3) over bar] c' and weaker polarization along [1 (1) over bar 00] m-direction, indicating different strain relaxation degrees. The theoretical model based on a k center dot p calculation revealed the dominant transitions from the conduction band to the valence band, explaining the experimental results.
Article
Multidisciplinary Sciences
Shao-Pin Chiu, C. C. Tsuei, Sheng-Shiuan Yeh, Fu-Chun Zhang, Stefan Kirchner, Juhn-Jong Lin
Summary: Triplet pairing has been observed in nonmagnetic CoSi2/TiSi2 heterostructures on silicon, indicating chiral p-wave pairing. This discovery is significant for topological materials and quantum technology research, and suggests potential applications of CoSi2 and TiSi2 in silicon-based integrated-circuit technology.
Article
Chemistry, Multidisciplinary
Maksim A. Pavlenko, Yuri A. Tikhonov, Anna G. Razumnaya, Valerii M. Vinokur, Igor A. Lukyanchuk
Summary: This study investigates the temperature dependence of polarization domains in dielectric/ferroelectric/dielectric heterostructures. Using phase-field modeling and analytical calculations, the temperature dependence of the dielectric constant of the ferroelectric layers and regions of negative capacitance are identified. This has important implications for implementing energy-efficient ferroelectric field-effect transistors.
Article
Chemistry, Physical
Tae Hyung Kim, Juho Lee, Ryong-Gyu Lee, Yong-Hoon Kim
Summary: In this study, a non-equilibrium first-principles simulation method based on the multi-space constrained-search density functional formalism is introduced for the computer-aided design of vertically stacked 2D van der Waals heterostructure devices. The research shows that the negative differential resistance (NDR) characteristics can be produced through the gating-induced mismatch between two graphene Dirac cones in energy-momentum space and the bias-dependent energetic shift of defect levels. Furthermore, the placement of carbon atoms substituted for nitrogen atoms on different layers of hBN significantly affects the device characteristics, emphasizing the importance of atomic details for 2D vdW devices.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Nanoscience & Nanotechnology
Lin Liu, Lin Lei, Xiaomei Lu, Yinsong Xia, Zijing Wu, Fengzhen Huang
Summary: In this study, ferroelectric BaTiO3 (BTO) films were deposited on low-resistance Si(100) substrates, forming Pt/BTO/p-Si/Pt samples. Negative capacitance (NC) values were directly measured at low frequencies with a DC bias, and the tunability of NC was observed due to the asymmetric interface. The analysis showed that, in addition to the displacement current related to electric polarization, there were also relaxation currents caused by interface charge injection and oxygen vacancy migration. This research provides a new perspective for the study of miniaturized and low-energy devices utilizing NC, and has great significance for the development of silicon-based ferroelectric devices.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Review
Chemistry, Physical
Yasemin Safak-Asar, Tarik Asar, Semsettin Altindal, Suleyman Ozcelik
JOURNAL OF ALLOYS AND COMPOUNDS
(2015)
Article
Materials Science, Multidisciplinary
Yasemin Safak Asar, Tarik Asar, Semsettin Altindal, Suleyman Ozcelik
PHILOSOPHICAL MAGAZINE
(2015)
Article
Physics, Multidisciplinary
Ahmet Kaya, Semsettin Altindal, Yasemin Safak Asar, Zekayi Sonmez
CHINESE PHYSICS LETTERS
(2013)
Article
Chemistry, Physical
Ozkan Vural, Yasemin Safak, Abdulmecit Turut, Semsettin Altindal
JOURNAL OF ALLOYS AND COMPOUNDS
(2012)
Article
Physics, Applied
Yasemin Safak, Murat Soylu, Fahrettin Yakuphanoglu, Semsettin Altindal
JOURNAL OF APPLIED PHYSICS
(2012)
Article
Engineering, Electrical & Electronic
Engin Arslan, Yasemin Safak, Ilke Tascioglu, Habibe Uslu, Ekmel Ozbay
MICROELECTRONIC ENGINEERING
(2010)
Article
Engineering, Electrical & Electronic
Engin Arslan, Serkan Butun, Yasemin Safak, Habibe Uslu, Ilke Tascioglu, Semsettin Altindal, Ekmel Ozbay
MICROELECTRONICS RELIABILITY
(2011)
Article
Engineering, Electrical & Electronic
Engin Arslan, Serkan Butun, Yasemin Safak, Huseyin Cakmak, Hongbo Yu, Ekmel Ozbay
MICROELECTRONICS RELIABILITY
(2011)
Article
Engineering, Electrical & Electronic
Seckin Altindal Yeriskin, Yasemin Safak Asar
Summary: The study found that a 5% doping ratio of graphene into PVA yielded the best performance for organic thin film, with certain parameters decreasing and barrier height increasing as the doping rate increased. Organic thin film with Gr:PVA can be preferred over traditional insulators due to lower cost/weight-D-it, higher barrier height, and easier production technique.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Multidisciplinary
Y. Safak Asar, A. Feizollahi Vahid, N. Basman, H. G. Cetinkaya, S. Altindal
Summary: A diamond-like carbon film (DLC) was deposited on a p-Si substrate to fabricate Al/DLC/p-Si/Au metal/interlayer/semiconductor (MIS) Schottky diodes (SDs). Analysis using SEM and XPS methods revealed that the DLC interfacial layer completely coated the silicon surface with spherical particles and islets. Measurements showed that the DLC film had outstanding characteristics as an interlayer, reducing surface states and other dislocations in SDs.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2023)
Article
Engineering, Electrical & Electronic
A. Feizollahi Vahid, S. Alptekin, N. Basman, M. Ulusoy, Y. Safak Asar, S. Altindal
Summary: To achieve greater barrier height in metal-interlayer-semiconductor (MIS) Schottky diodes (SDs), various materials are used as interlayer at M/S interface. Among these materials, diamond-like carbon (DLC) is chosen due to its exceptional qualities. A copper-doped DLC (CuDLC) nanocomposite film is electrochemically formed as an interlayer to create the Al/(Cu-DLC)/p-Si/Au MIS type SD. The impedance spectroscopy (IS) technique is used to analyze the electrical properties of the device.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Engineering, Electrical & Electronic
Yasemin Safak Asar, Omer Sevgili, Semsettin Altindal
Summary: The frequency and voltage dependence of various parameters of Au/(Carbon Nanosheet-PVP composite)/n-Si capacitors were investigated using impedance spectroscopy. The response of these parameters to frequency can be attributed to interfacial polarization and a special distribution of interface states. The use of the Carbon Nanosheet-PVP composite as an interfacial layer has improved device performance over a wide range of frequencies and voltages.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Materials Science, Multidisciplinary
S. Altindal, Y. Safak Asar, A. Kaya, Z. Sonmez
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS
(2012)
Article
Materials Science, Multidisciplinary
H. Kanbur, S. Altindal, T. Mammadov, Y. Safak
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS
(2011)
Article
Materials Science, Multidisciplinary
I. Tascioglu, H. Uslu, Y. Safak, E. Ozbay
OPTOELECTRONICS AND ADVANCED MATERIALS-RAPID COMMUNICATIONS
(2010)