Article
Crystallography
Lian Wei, Yi Miao, Rui Pan, Wang-wei Zhang, Chen Li, Hong Lu, Yan-Feng Chen
Summary: The study found that Ge1-xSnx alloy films are highly strained even after Sn segregation, and increasing the Sn composition shrinks the bandgap of Ge1-xSnx. Low growth temperatures and high growth rates are beneficial for achieving higher Sn compositions, while strain plays an important role in limiting Sn incorporation.
JOURNAL OF CRYSTAL GROWTH
(2021)
Article
Physics, Applied
Zhiwen Liang, Ye Yuan, Pengwei Wang, JunJie Kang, Qi Wang, Guoyi Zhang
Summary: This study comprehensively investigated the ex situ sputtered AlN buffer and GaN epilayer grown by metalorganic chemical vapor deposition. The study revealed that the AlN buffer deposited by sputtering technique could be oxidized in the atmosphere, which significantly affected the characteristics of the GaN epilayer. This finding has important guiding significance for the growth of high-quality III-nitride materials.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
S. A. Garcia Hernandez, V. D. Compean Garcia, E. Prado Navarrete, E. Lopez Luna, M. A. Vidal
Summary: In this study, the mechanical properties of cubic indium nitride were investigated using a Berkovich indenter, with a hardness value of 12.5 GPa, Young's modulus value of 365.6 GPa, and a Poisson's ratio of 0.3.
Article
Chemistry, Multidisciplinary
Djuro Bikaljevic, Carmen Gonzalez-Orellana, Marina Pena-Diaz, Dominik Steiner, Jan Dreiser, Pierluigi Gargiani, Michael Foerster, Miguel Angel Nino, Lucia Aballe, Sandra Ruiz-Gomez, Niklas Friedrich, Jeremy Hieulle, Li Jingcheng, Maxim Ilyn, Celia Rogero, Jose Ignacio Pascual
Summary: Metal dihalides, such as NiBr2, exhibit promising semiconducting and magnetic behavior on Au(111) substrates, showing potential for applications in tunneling junctions and low-dimensional devices. Experiments using various techniques revealed competing layer structures of NiBr2 at the interface, with a magnetically ordered state below 27K attributed to a non-collinear magnetic structure in the single layer.
Article
Chemistry, Physical
Sergij Chusnutdinow, Alexander Kazakov, Rafal Jakiela, Michal Szot, Steffen Schreyeck, Karl Brunner, Grzegorz Karczewski
Summary: The properties of Pb1-xMnxTe/CdTe multilayer composite grown on a GaAs substrate by molecular beam epitaxy were investigated. Morphological characterization, electron transport and optical spectroscopy measurements were conducted, along with X-ray diffraction, scanning electron microscopy, and secondary ion mass spectroscopy. The study focused on the sensing properties of photoresistors made of Pb1-xMnxTe/CdTe in the infrared spectral region. It was found that the presence of Mn in the conductive layers shifted the cut-off wavelength towards blue and weakened the spectral sensitivity of the photoresistors due to the increase in energy gap and deterioration in crystal quality caused by the presence of Mn atoms.
Article
Physics, Applied
Ding Wang, Shubham Mondal, Jiangnan Liu, Mingtao Hu, Ping Wang, Samuel Yang, Danhao Wang, Yixin Xiao, Yuanpeng Wu, Tao Ma, Zetian Mi
Summary: We demonstrate ferroelectric switching in yttrium-doped nitride semiconductors. Yttrium 0.07Al0.93N films were grown on GaN/sapphire templates and exhibited a coercive field of 6 MV/cm and a switchable polarization of 130 mu C/cm(2). Ferroelectric switching was confirmed through capacitance-voltage loops and polarity-sensitive wet etching. This study expands the family of nitride ferroelectrics and opens up possibilities for applications in III-nitride based devices.
APPLIED PHYSICS LETTERS
(2023)
Article
Chemistry, Multidisciplinary
Rahmat Hadi Saputro, Ryo Matsumura, Naoki Fukata
Summary: This study reveals the mechanism of dopant redistribution in Sb-doped Ge epitaxial films grown by molecular beam epitaxy, providing insights into the behavior of substituted Sb atoms in forming n-type Ge films. The understanding of these processes opens up possibilities for achieving n(+)-Ge thin films for Ge-based devices with improved electrical properties.
CRYSTAL GROWTH & DESIGN
(2021)
Article
Physics, Applied
Ping Wang, Ding Wang, Nguyen M. Vu, Tony Chiang, John T. Heron, Zetian Mi
Summary: Ferroelectricity has been successfully demonstrated in ScxAl1-xN epitaxial films grown on GaN templates by molecular beam epitaxy, showing distinct polarization switching and excellent properties, such as a high coercive field and long polarization retention time. This achievement opens up possibilities for integrating high-performance ferroelectric functionality into established semiconductor platforms for various electronic and photonic device applications.
APPLIED PHYSICS LETTERS
(2021)
Article
Chemistry, Multidisciplinary
Mario F. Zscherp, Nils Mengel, Detlev M. Hofmann, Vitalii Lider, Badrosadat Ojaghi Dogahe, Celina Becker, Andreas Beyer, Kerstin Volz, Joerg Schoermann, Sangam Chatterjee
Summary: This study successfully optimized the quality of c-GaN epitaxial layers by introducing pre-growth treatments and buffer layers, achieving nearly perfect crystallinity and smooth surfaces and interfaces. The optimized growth parameters resulted in extremely small surface roughness and very limited stacking fault densities in phase pure c-GaN layers. The high structural quality of the epitaxial layers was further confirmed through photoluminescence spectroscopy.
CRYSTAL GROWTH & DESIGN
(2022)
Article
Physics, Multidisciplinary
Antian Du, Chunfang Cao, Shixian Han, Hailong Wang, Qian Gong
Summary: This paper reports the realization of high performance 1.31µm InAs/GaAs quantum dot lasers on a Si substrate with all-MBE. Under continuous wave operation mode, Si-based InAs quantum dot lasers with a narrow ridge structure achieved a low threshold current density of 375 A cm(-2), high output power of 63 mW, and high operating temperature of 80°C. It has great potential for application in the development of Si-based photonic integration circuits.
Article
Chemistry, Multidisciplinary
Vladimir G. Dubrovskii, Simon Escobar Steinvall, Virginie de Mestral, Rajrupa Paul, Jean-Baptiste Leran, Mahdi Zamani, Elias Z. Stutz, Anna Fontcuberta Morral
Summary: Selective area growth of Zn3P2 on InP provides high-quality semiconductor nanostructures made of earth-abundant elements. In the precoalescence stage, Zn3P2 emerges in the form of nanoislands and undergoes a shape transformation. The results are presented in dimensionless variables, allowing simultaneous understanding of islands grown in differently sized pinholes and for different growth times.
CRYSTAL GROWTH & DESIGN
(2021)
Review
Physics, Condensed Matter
Malgorzata Gorska, Lukasz Kilanski, Andrzej Lusakowski
Summary: This paper describes diluted magnetic semiconductors (DMS) and their magnetic properties, comparing the differences and similarities in magnetic properties among different types of DMS. The influence of material's crystalline and electronic structure on its magnetic properties is examined, and experimental methods for determining exchange parameters are introduced. The development of material technology is also traced in the paper.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Spectroscopy
Jon Schlipf, Henriette Tetzner, Davide Spirito, Costanza L. Manganelli, Giovanni Capellini, Michael R. S. Huang, Christoph T. Koch, Caterina J. Clausen, Ahmed Elsayed, Michael Oehme, Stefano Chiussi, Joerg Schulze, Inga A. Fischer
Summary: In this study, we investigated the Raman shift in silicon-germanium-tin alloys with high silicon content. By measuring and analyzing the Raman shifts of the three most prominent modes, we were able to calculate the composition and strain of the alloys. Our findings demonstrate that Raman measurements can serve as a local, fast, and nondestructive characterization technique for a wider compositional range of these ternary alloys.
JOURNAL OF RAMAN SPECTROSCOPY
(2021)
Article
Materials Science, Multidisciplinary
Michel Lannoo, P. Tim Prins, Zeger Hens, Daniel Vanmaekelbergh, Christophe Delerue
Summary: By studying the absorptance spectra of nanometer-thin layers of various semiconductors, researchers have found that the optical absorptance exhibits similar characteristics to graphene, with marked plateaus at integer values of pi alpha. This quantization of absorptance is universal in semiconductor quantum wells, as long as excitonic effects are weak, and is not specific to graphene. The physical origin of this universality is explained using analytical models, which show that the absorptance is ruled by pi alpha independent of the material characteristics.
Article
Nanoscience & Nanotechnology
Kenny Huynh, Michael E. Liao, Akhil Mauze, Takeki Itoh, Xingxu Yan, James S. Speck, Xiaoqing Pan, Mark S. Goorsky
Summary: The orientational dependence of interfacial reaction between aluminum and different β-Ga2O3 substrates (010, (001), and ((2) over bar 01)) was investigated. It was found that the orientation of β-Ga2O3 substrates influences the formation of aluminum oxide layers and diffusional pathways.
Article
Chemistry, Multidisciplinary
Piyush Agarwal, Rohit Medwal, Abhishek Kumar, Hironori Asada, Yasuhiro Fukuma, Rajdeep Singh Rawat, Marco Battiato, Ranjan Singh
Summary: The phase reversal of terahertz spin current induced by a femtosecond light pulse demonstrates a new paradigm for ultra-low-power hybrid electronics and photonics, enabled by the interplay of charge, spin, thermal, and optical signals.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Physics, Applied
Utkarsh Shashank, Rohit Medwal, Yoji Nakamura, John Rex Mohan, Razia Nongjai, Asokan Kandasami, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: In this study, the damping-like torque efficiency was increased more than 3.5 times by using a better approach of low energy O+ ion implantation in modified Pt-oxide. The spin transmission was improved with a smaller trade-off in the longitudinal resistivity, and the enhanced spin Hall effect in O-implanted Pt was attributed to a side-jumping mechanism. The torques from the O-implanted Pt remained twofold and symmetrical, allowing for quantification using spin-torque ferromagnetic resonance-based line shape analysis.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Masaaki Imamura, Hironori Asada, Ryo Nishimura, Daisuke Tashima, Jiro Kitagawa
Summary: In this study, we optimized each component of a spin thermoelectric generator and observed its effect on the voltage. By substituting bismuth and aluminum for yttrium and iron in the iron garnet film, a significant increase in voltage was observed.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Physical
Garima Vashisht, Utkarsh Shashank, Surbhi Gupta, Rohit Medwal, C. L. Dong, C. L. Chen, K. Asokan, Y. Fukuma, S. Annapoorni
Summary: FeCo was found to inhibit the crystalline growth of FePt and exhibit soft ferromagnetic in-plane behavior with defect-driven hard ferromagnetic properties in the out-plane configuration. Only FePt showed an out-plane magnetization component in FeCo/FePt/Si, and the local coordination of Co remained similar regardless of stack order, while the local geometry of Fe varied due to different crystallinity of FePt in the two series.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
M. Imamura, H. Asada, R. Nishimura, Y. Kano, D. Tashima, J. Kitagawa
Summary: Liquid phase epitaxial Bi-substituted YIG films exhibit a large growth-induced magnetic anisotropy perpendicular to the film surface. The anisotropy depends on the melt composition and supercooling in the growth process. Even at a Bi content of 0, the film shows a significant anisotropy. The spin-orbital coupling enhances the thermal energy transfer and increases spin currents for spin-thermoelectric generation.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Avinash Chaurasiya, Ziqi Li, Rohit Medwal, Surbhi Gupta, John Rex Mohan, Yasuhiro Fukuma, Hironori Asada, Elbert E. M. Chia, Rajdeep Singh Rawat
Summary: This study demonstrates the electric field-mediated piezoelectric strain control of photogenerated THz spin current pulse from a multiferroic spintronic emitter, opening up new possibilities for the development of efficient on-chip THz spintronics devices.
ADVANCED OPTICAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Utkarsh Shashank, Angshuman Deka, Chen Ye, Surbhi Gupta, Rohit Medwal, Rajdeep Singh Rawat, Hironori Asada, X. Renshaw Wang, Yasuhiro Fukuma
Summary: This study focuses on the quasi-two-dimensional electron gas between insulating SrTiO3 and two types of aluminum-based amorphous insulators, and estimates their charge-to-spin conversion efficiency. The contribution of oxygen vacancy is investigated. A mechanism to explain the experimental results is proposed and a reliable method to estimate the thickness of the quasi-two-dimensional electron gas is developed. The findings show the significance of defects in charge-spin interconversion and offer a way to enhance it through defect engineering.
PHYSICA STATUS SOLIDI-RAPID RESEARCH LETTERS
(2023)
Article
Nanoscience & Nanotechnology
Masaaki Imamura, Hironori Asada, Yuya Kano, Ryota Matsuda, Daisuke Tashima, Jiro Kitagawa
Summary: We previously proposed that effective thermal-energy transfer in Bi:YIG LPE films occurs through enhanced SOC, and STE generation in Pt layer is increased by spin pumping from Bi:YIG film. However, we couldn't specifically relate the underlying mechanism to the driving force for spin current generation. In this paper, we discuss the origin of the driving force for increased spin currents through enhanced SOC in LPE YIG films.
Article
Physics, Applied
Sourabh Manna, Rohit Medwal, Surbhi Gupta, John Rex Mohan, Yasuhiro Fukuma, Rajdeep Singh Rawat
Summary: Ferromagnet/nonmagnet (FM/NM) bilayer-based spin Hall nano-oscillators (SHNOs) have potential for low-power physical reservoir computing systems. However, most studies require an external biasing magnetic field, limiting their practical implementation. This study demonstrates biasing field-free operation of a FM/NM bilayer-based SHNO using magnetic anisotropy control, which can significantly modify the auto-oscillation characteristics and reduce the threshold current for auto-oscillation.
APPLIED PHYSICS LETTERS
(2023)
Article
Engineering, Electrical & Electronic
Arun Jacob Mathew, John Rex Mohan, Ruoyan Feng, Rohit Medwal, Surbhi Gupta, Rajdeep Singh Rawat, Yasuhiro Fukuma
Summary: In this study, a spintronic device called spin Hall oscillator (SHO) is used as the reservoir in reservoir computing (RC) architecture. By evaluating the memory capacity of the SHO system with micromagnetic simulations, it is found that the reservoir's memory capacity is correlated with its efficiency in performing temporal tasks.
IEEE TRANSACTIONS ON MAGNETICS
(2023)
Article
Materials Science, Multidisciplinary
Utkarsh Shashank, Yoji Nakamura, Yu Kusaba, Takafumi Tomoda, Razia Nongjai, Asokan Kandasami, Rohit Medwal, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: Recent studies have shown that incorporating nonmetallic lighter elements into 5d transition metals can enhance the efficiency of dampinglike torque. This finding is important for the development of low-power and robust magnetic memory.
Article
Physics, Multidisciplinary
Angshuman Deka, Bivas Rana, Ryo Anami, Katsuya Miura, Hiromasa Takahashi, YoshiChika Otani, Yasuhiro Fukuma
Summary: This study investigates the application of electric field controlled magnetization dynamics in low-power spintronic devices. Electric field induced parametric excitation was successfully achieved by using interfacial in-plane magnetic anisotropy. The excitation wavelength can be tuned by changing the input power and frequency of the applied voltage. A phenomenological model was developed to explain the role of electric field torque. This research offers an opportunity for developing nanoscale magnonic devices and exploring nonlinear dynamics in nanomagnetic systems.
PHYSICAL REVIEW RESEARCH
(2022)
Article
Quantum Science & Technology
Utkarsh Shashank, Rohit Medwal, Taiga Shibata, Razia Nongjai, Joseph Vimal Vas, Martial Duchamp, Kandasami Asokan, Rajdeep Singh Rawat, Hironori Asada, Surbhi Gupta, Yasuhiro Fukuma
Summary: Efficient charge-spin interconversion is crucial for understanding the functionalities of spin-orbit torque in energy-efficient and high-speed spintronic devices. A new spin Hall material, Pt(S), is reported in this study, demonstrating significantly higher conversion efficiency compared to pristine Pt, along with large spin Hall angle and viable electrical and spin Hall conductivity.
ADVANCED QUANTUM TECHNOLOGIES
(2021)