Mingming Tian, Qian Chen, Meiyang Ma, Wei Jiang, Qingjie Guo, Ruobai Liu, Jun Du, Xuezhong Ruan, Zhongming Zeng, Juan-Carlos Rojas-Sánchez, Stéphane Mangin, Zhaocong Huang, Yongbing Xu, Ya Zhai
Spin transmission is critical for the functionality of logic circuits, magnetic random-access memories, and magnetic sensors. Rare earth (RE) metals, which are promising candidates for tuning spin transmission, can form antiferromagnetically coupled interfaces with ferromagnetic layers. In this study, we investigate the laser-induced ultrafast spin injection from permalloy (Py) into the RE metal holmium (Ho), modulated by interfacial engineering and varying the external magnetic field strength. The antiferromagnetically coupled interface between Py and Ho is confirmed by x-ray magnetic circular dichroism, and its correlation with spin dynamic damping is revealed by time-resolved magneto-optical Kerr effect. More importantly, we demonstrate the effective modulation of spin transmission through an external magnetic field. At the Py/Ho interface, a substantial spin-mixing conductance (SMC) of approximately 7.71 × 1015 cm−2 is observed, which can be modulated by approximately 35% under an external magnetic field. The applied high magnetic fields are found to suppress the large SMC, primarily due to the modified sperimagnetic structure at the Py/Ho interface. These findings demonstrate the excellent spin transmission efficiency in the Py/Ho system, providing a promising approach for magneto-dynamics modulation in spintronic devices.
{"title":"Tunable spin dynamic damping and interfacial spin transparency in Py/Ho through magnetic field modulation","authors":"Mingming Tian, Qian Chen, Meiyang Ma, Wei Jiang, Qingjie Guo, Ruobai Liu, Jun Du, Xuezhong Ruan, Zhongming Zeng, Juan-Carlos Rojas-Sánchez, Stéphane Mangin, Zhaocong Huang, Yongbing Xu, Ya Zhai","doi":"10.1063/5.0253095","DOIUrl":"https://doi.org/10.1063/5.0253095","url":null,"abstract":"Spin transmission is critical for the functionality of logic circuits, magnetic random-access memories, and magnetic sensors. Rare earth (RE) metals, which are promising candidates for tuning spin transmission, can form antiferromagnetically coupled interfaces with ferromagnetic layers. In this study, we investigate the laser-induced ultrafast spin injection from permalloy (Py) into the RE metal holmium (Ho), modulated by interfacial engineering and varying the external magnetic field strength. The antiferromagnetically coupled interface between Py and Ho is confirmed by x-ray magnetic circular dichroism, and its correlation with spin dynamic damping is revealed by time-resolved magneto-optical Kerr effect. More importantly, we demonstrate the effective modulation of spin transmission through an external magnetic field. At the Py/Ho interface, a substantial spin-mixing conductance (SMC) of approximately 7.71 × 1015 cm−2 is observed, which can be modulated by approximately 35% under an external magnetic field. The applied high magnetic fields are found to suppress the large SMC, primarily due to the modified sperimagnetic structure at the Py/Ho interface. These findings demonstrate the excellent spin transmission efficiency in the Py/Ho system, providing a promising approach for magneto-dynamics modulation in spintronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"197 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640060","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fan Zhang, Ruiheng Geng, Xinyue Huang, Xiaotong Peng, Jun Xu, Xian Chen, Chenbo Zhang
Pyroelectric energy conversion shows potential for low-grade waste heat harvesting. In this work, we design and investigate the SrxBa1−xNb2O6 material at x = 0.6 (SBN60), focusing on the role of oxygen vacancies and their impacts on pyroelectric performance. By employing floating-zone synthesis with proper heat-treatment process, we systematically tune oxygen vacancies and reveal their dual effect: oxygen vacancies enhance the pyroelectric figure-of-merit, while removing oxygen vacancies extends the effective lifetime in one-charge pyroelectric energy conversion. We discover that the phase transition in a heat-treated single crystal SBN60 device helps achieve stable electricity generation for approximately 7000 cycles in 30 h with enhanced functional reversibility. The dual effect of oxygen vacancies on the coupling of pyroelectricity and effective lifetime provides a useful strategy to design high-performance pyroelectric materials, especially for one-charge pyroelectric energy conversion, offering a practical solution for real-world applications of pyroelectric devices.
{"title":"Enhanced figure-of-merit and fatigue resistance of strontium barium niobate for pyroelectric energy conversion","authors":"Fan Zhang, Ruiheng Geng, Xinyue Huang, Xiaotong Peng, Jun Xu, Xian Chen, Chenbo Zhang","doi":"10.1063/5.0256350","DOIUrl":"https://doi.org/10.1063/5.0256350","url":null,"abstract":"Pyroelectric energy conversion shows potential for low-grade waste heat harvesting. In this work, we design and investigate the SrxBa1−xNb2O6 material at x = 0.6 (SBN60), focusing on the role of oxygen vacancies and their impacts on pyroelectric performance. By employing floating-zone synthesis with proper heat-treatment process, we systematically tune oxygen vacancies and reveal their dual effect: oxygen vacancies enhance the pyroelectric figure-of-merit, while removing oxygen vacancies extends the effective lifetime in one-charge pyroelectric energy conversion. We discover that the phase transition in a heat-treated single crystal SBN60 device helps achieve stable electricity generation for approximately 7000 cycles in 30 h with enhanced functional reversibility. The dual effect of oxygen vacancies on the coupling of pyroelectricity and effective lifetime provides a useful strategy to design high-performance pyroelectric materials, especially for one-charge pyroelectric energy conversion, offering a practical solution for real-world applications of pyroelectric devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"183 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scanning tunneling spectroscopy (STS) has played an important role in determining the electronic band structures of semiconductors. However, the tip-induced band bending (TIBB) could strongly affect the measured valence and conduction band edges, which are of vital importance for a semiconductor. In the literature, the presence or absence of the TIBB effect in a given STS measurement is often not discussed thoroughly. In this work, we quantitatively investigate the TIBB effect in MoS2 with varying thicknesses using light-modulated contact-mode STS. Our results demonstrate that the TIBB effect is strongly dependent on the thickness of MoS2. With thin MoS2 of a few atomic layers (several nanometers), the TIBB approaches zero, and the measured STS can accurately reflect the band edges. While for thicker MoS2 of ∼100 nm, the TIBB can be as large as ∼1 eV. This work clarifies the ambiguity about the TIBB effect and provides a foundation for the interpretation of STS data on atomically thin semiconductors.
{"title":"Probing thickness-dependent tip-induced band bending in MoS2","authors":"Jian Liao, Takashi Taniguchi, Kenji Watanabe, Jiamin Xue","doi":"10.1063/5.0252812","DOIUrl":"https://doi.org/10.1063/5.0252812","url":null,"abstract":"Scanning tunneling spectroscopy (STS) has played an important role in determining the electronic band structures of semiconductors. However, the tip-induced band bending (TIBB) could strongly affect the measured valence and conduction band edges, which are of vital importance for a semiconductor. In the literature, the presence or absence of the TIBB effect in a given STS measurement is often not discussed thoroughly. In this work, we quantitatively investigate the TIBB effect in MoS2 with varying thicknesses using light-modulated contact-mode STS. Our results demonstrate that the TIBB effect is strongly dependent on the thickness of MoS2. With thin MoS2 of a few atomic layers (several nanometers), the TIBB approaches zero, and the measured STS can accurately reflect the band edges. While for thicker MoS2 of ∼100 nm, the TIBB can be as large as ∼1 eV. This work clarifies the ambiguity about the TIBB effect and provides a foundation for the interpretation of STS data on atomically thin semiconductors.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Low-dimensional materials have attracted significant attention due to their unique physical properties and broad potential applications. Antimony selenide is well known for its thermoelectric properties. However, the on-surface synthesis of chain-like structures with varying stoichiometries remains challenging. In this study, we employ scanning tunneling microscopy/spectroscopy and density functional theory calculations to investigate the epitaxial growth of SbSe chain structures. With increasing deposition of Sb and Se, a transition is observed in both the structural and electronic properties, shifting from semiconducting mixed chains to metallic uniform tri-chains. X-ray photoelectron spectroscopy confirms the elemental composition and helps determine the stoichiometries. Theoretical calculations show that the mixed-chain phase is an indirect bandgap semiconductor with a bandgap of 0.17 eV, and that spin–orbit coupling induces band splitting. In contrast, the tri-chain phase, formed by weak van der Waals interactions between chains within the unit cell, undergoes a semiconductor-to-metal transition due to strong hybridization near the Fermi level. These findings not only provide a strategy for tuning the electronic properties of one-dimensional materials but also provide valuable insights for the design of thermoelectric and quantum materials, with potential applications in next-generation electronic devices.
{"title":"Surface-driven structural evolution and electronic transition of SbSe chains on Au(111)","authors":"Li Li, Qiwei Tian, Shuangping Liao, Sahar Izadi Vishkayi, Li Zhang, Long-Jing Yin, Yuan Tian, Meysam Bagheri Tagani, Lijie Zhang, Zhihui Qin","doi":"10.1063/5.0260537","DOIUrl":"https://doi.org/10.1063/5.0260537","url":null,"abstract":"Low-dimensional materials have attracted significant attention due to their unique physical properties and broad potential applications. Antimony selenide is well known for its thermoelectric properties. However, the on-surface synthesis of chain-like structures with varying stoichiometries remains challenging. In this study, we employ scanning tunneling microscopy/spectroscopy and density functional theory calculations to investigate the epitaxial growth of SbSe chain structures. With increasing deposition of Sb and Se, a transition is observed in both the structural and electronic properties, shifting from semiconducting mixed chains to metallic uniform tri-chains. X-ray photoelectron spectroscopy confirms the elemental composition and helps determine the stoichiometries. Theoretical calculations show that the mixed-chain phase is an indirect bandgap semiconductor with a bandgap of 0.17 eV, and that spin–orbit coupling induces band splitting. In contrast, the tri-chain phase, formed by weak van der Waals interactions between chains within the unit cell, undergoes a semiconductor-to-metal transition due to strong hybridization near the Fermi level. These findings not only provide a strategy for tuning the electronic properties of one-dimensional materials but also provide valuable insights for the design of thermoelectric and quantum materials, with potential applications in next-generation electronic devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"59 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yuchao Zhang, Shanzheng Du, Xiaochi Liu, Yahua Yuan, Jian Sun
The flexoelectric effect, which couples strain gradients to electric polarization, provides a promising method for ferroelectric domain engineering without the need for external electric fields. Applying localized forces to the surface of ferroelectric materials using scanning probes can generate strain gradients that induce domain reconfigurations. In this study, we present an alternative approach to flexoelectric-induced domain engineering in suspended two-dimensional CuInP2S6 (CIPS) membranes by varying the ambient pressure. By capping CIPS over cavity holes, internal air pressurization induces bulging, which results in unique encircled domain configurations governed by local strain gradients showing upward and downward polarizations at the center and the edge of the suspended membrane, respectively. Furthermore, this domain configuration can be bidirectionally modulated by varying the ambient pressure. We demonstrate reversible variations in domain size, driven by topographic changes that redistribute the strain gradient. Our findings demonstrate that ambient pressure can be used to engineer domains in suspended ferroelectric membranes, opening avenues for the development of emerging ferroelectric devices that are sensitive to ambient pressure.
{"title":"Ambient pressure-induced domain engineering in suspended CuInP2S6 membrane","authors":"Yuchao Zhang, Shanzheng Du, Xiaochi Liu, Yahua Yuan, Jian Sun","doi":"10.1063/5.0251656","DOIUrl":"https://doi.org/10.1063/5.0251656","url":null,"abstract":"The flexoelectric effect, which couples strain gradients to electric polarization, provides a promising method for ferroelectric domain engineering without the need for external electric fields. Applying localized forces to the surface of ferroelectric materials using scanning probes can generate strain gradients that induce domain reconfigurations. In this study, we present an alternative approach to flexoelectric-induced domain engineering in suspended two-dimensional CuInP2S6 (CIPS) membranes by varying the ambient pressure. By capping CIPS over cavity holes, internal air pressurization induces bulging, which results in unique encircled domain configurations governed by local strain gradients showing upward and downward polarizations at the center and the edge of the suspended membrane, respectively. Furthermore, this domain configuration can be bidirectionally modulated by varying the ambient pressure. We demonstrate reversible variations in domain size, driven by topographic changes that redistribute the strain gradient. Our findings demonstrate that ambient pressure can be used to engineer domains in suspended ferroelectric membranes, opening avenues for the development of emerging ferroelectric devices that are sensitive to ambient pressure.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"121 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A low-noise superconducting quantum interference device (dc-SQUID) with simplified design and readout electronics is highly desirable for various applications. We demonstrate that introducing an asymmetric shunt resistor significantly enhances the noise performance while maintaining the inherent simplicity and tunability of the SQUID design. By optimizing the asymmetry factor, our asymmetric shunted second-order gradient SQUID current sensor reaches a low white flux noise of 0.65 μΦ0/√Hz using a direct readout strategy, representing a threefold improvement over its symmetric counterpart. This noise level surpasses that of the SQUID with the additional positive feedback method and is comparable to the series SQUID arrays, making the asymmetric shunted SQUID suitable for meeting the readout requirements of various scientific instruments.
{"title":"Characterization and design of a low-noise second-order gradient SQUID with asymmetric shunt resistors","authors":"Yuxiao Guo, Jinjin Li, Xiaolong Xu, Shijian Wang, Xueshen Wang, Jian Chen, Qing Zhong","doi":"10.1063/5.0245555","DOIUrl":"https://doi.org/10.1063/5.0245555","url":null,"abstract":"A low-noise superconducting quantum interference device (dc-SQUID) with simplified design and readout electronics is highly desirable for various applications. We demonstrate that introducing an asymmetric shunt resistor significantly enhances the noise performance while maintaining the inherent simplicity and tunability of the SQUID design. By optimizing the asymmetry factor, our asymmetric shunted second-order gradient SQUID current sensor reaches a low white flux noise of 0.65 μΦ0/√Hz using a direct readout strategy, representing a threefold improvement over its symmetric counterpart. This noise level surpasses that of the SQUID with the additional positive feedback method and is comparable to the series SQUID arrays, making the asymmetric shunted SQUID suitable for meeting the readout requirements of various scientific instruments.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"16 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mahendra DC, Punyashloka Debashis, Christopher Gay, Jennifer Lux, Yu Zhang, Dominique Adams, Fen Xue, Carly Rogan, Tyrone Wilson, Raphael Toku, Joshua Kevek, Tristan A Tronic, Scott B. Clendenning, Adedapo A. Oni, Marko Radosavljevic, Shan X. Wang, Ian A. Young
We demonstrate the unconventional and conventional spin-to-charge conversion (SCC) in MnPd3 using local SCC device at room temperature. The low crystal symmetry along the (114) growth direction allows unconventional SCC in MnPd3. The figure of merit of in-plane spin polarization in unconventional SCC is determined to be 4.70%. Unconventional and conventional SCCs are promising for magnetization detection in spintronics and magnetoelectric devices.
{"title":"Unconventional spin-to-charge conversion in MnPd3","authors":"Mahendra DC, Punyashloka Debashis, Christopher Gay, Jennifer Lux, Yu Zhang, Dominique Adams, Fen Xue, Carly Rogan, Tyrone Wilson, Raphael Toku, Joshua Kevek, Tristan A Tronic, Scott B. Clendenning, Adedapo A. Oni, Marko Radosavljevic, Shan X. Wang, Ian A. Young","doi":"10.1063/5.0251602","DOIUrl":"https://doi.org/10.1063/5.0251602","url":null,"abstract":"We demonstrate the unconventional and conventional spin-to-charge conversion (SCC) in MnPd3 using local SCC device at room temperature. The low crystal symmetry along the (114) growth direction allows unconventional SCC in MnPd3. The figure of merit of in-plane spin polarization in unconventional SCC is determined to be 4.70%. Unconventional and conventional SCCs are promising for magnetization detection in spintronics and magnetoelectric devices.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"43 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yangyang Xu, Yumei Zhou, Yu Wang, Sen Yang, Dezhen Xue
This study investigates the avalanche dynamics of ferroelectric domain switching in barium titanate single crystals across a range of temperatures using acoustic emission techniques. Ferroelectric domain switching induced by an electric field exhibits scale-invariant avalanche dynamics, with the energy exponent increasing from 1.63 ± 0.067 at room temperature to 1.92 ± 0.045 near the Curie point, before decreasing at higher temperatures. This peak in the exponent is attributed to the interplay between equilibrium critical fluctuations and avalanche criticality. As the temperature approaches the Curie point, smaller domains and reduced polarization promote lower-energy switching, increasing the energy exponent. Near the Curie temperature, equilibrium fluctuations further modify the energy landscape, likely generating more phase boundaries and amplifying the energy exponent. Above the Curie temperature, electric field-induced phase transition dominates the switching process, where the higher energy barrier hinders switching, resulting in more energetic events and a lower energy exponent. Across all temperatures, waiting time distributions exhibit double power-law behavior, with exponents of −1 ± 0.05 for short times and −2 ± 0.10 for long times, while aftershock activity follows Omori's law with an exponent close to −1, indicating robust temporal correlations in ferroelectric domain switching. This study underscores that the avalanche dynamics of ferroelectric domain switching can be effectively modulated by temperature.
{"title":"Influence of temperature on the avalanche dynamics of ferroelectric domain switching in barium titanate single crystals","authors":"Yangyang Xu, Yumei Zhou, Yu Wang, Sen Yang, Dezhen Xue","doi":"10.1063/5.0246599","DOIUrl":"https://doi.org/10.1063/5.0246599","url":null,"abstract":"This study investigates the avalanche dynamics of ferroelectric domain switching in barium titanate single crystals across a range of temperatures using acoustic emission techniques. Ferroelectric domain switching induced by an electric field exhibits scale-invariant avalanche dynamics, with the energy exponent increasing from 1.63 ± 0.067 at room temperature to 1.92 ± 0.045 near the Curie point, before decreasing at higher temperatures. This peak in the exponent is attributed to the interplay between equilibrium critical fluctuations and avalanche criticality. As the temperature approaches the Curie point, smaller domains and reduced polarization promote lower-energy switching, increasing the energy exponent. Near the Curie temperature, equilibrium fluctuations further modify the energy landscape, likely generating more phase boundaries and amplifying the energy exponent. Above the Curie temperature, electric field-induced phase transition dominates the switching process, where the higher energy barrier hinders switching, resulting in more energetic events and a lower energy exponent. Across all temperatures, waiting time distributions exhibit double power-law behavior, with exponents of −1 ± 0.05 for short times and −2 ± 0.10 for long times, while aftershock activity follows Omori's law with an exponent close to −1, indicating robust temporal correlations in ferroelectric domain switching. This study underscores that the avalanche dynamics of ferroelectric domain switching can be effectively modulated by temperature.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"13 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143635361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
H. W. T. Morgan, R. Elwell, J. E. S. Terhune, H. B. Tran Tan, U. C. Perera, A. Derevianko, A. N. Alexandrova, E. R. Hudson
The recent laser excitation of the 229Th isomeric transition in a solid-state host opens the door for a portable solid-state nuclear optical clock. However, at present, the vacuum-ultraviolet laser systems required for clock operation are not conducive to a fieldable form factor. Here, we propose a possible solution to this problem by using 229Th-doped nonlinear optical crystals, which would allow clock operation without a vacuum-ultraviolet laser system and without the need of maintaining the crystal under vacuum. We investigate electronic properties and thorium doping in BaMgF4 and BaZnF4 with density functional theory, predicting BaMgF4 to be the superior material, and evaluate the performance of a Th:BaMgF4 clock.
{"title":"Proposal and theoretical investigation of 229Th-doped nonlinear optical crystals for compact solid-state clocks","authors":"H. W. T. Morgan, R. Elwell, J. E. S. Terhune, H. B. Tran Tan, U. C. Perera, A. Derevianko, A. N. Alexandrova, E. R. Hudson","doi":"10.1063/5.0247867","DOIUrl":"https://doi.org/10.1063/5.0247867","url":null,"abstract":"The recent laser excitation of the 229Th isomeric transition in a solid-state host opens the door for a portable solid-state nuclear optical clock. However, at present, the vacuum-ultraviolet laser systems required for clock operation are not conducive to a fieldable form factor. Here, we propose a possible solution to this problem by using 229Th-doped nonlinear optical crystals, which would allow clock operation without a vacuum-ultraviolet laser system and without the need of maintaining the crystal under vacuum. We investigate electronic properties and thorium doping in BaMgF4 and BaZnF4 with density functional theory, predicting BaMgF4 to be the superior material, and evaluate the performance of a Th:BaMgF4 clock.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"40 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640476","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yunjian Hu, Danni Su, Tiecheng Luo, Yuru Lai, Zhengyi Liao, Chunhong Zeng, Xiaodong Zhang, Man Hoi Wong, Zimin Chen, Yanli Pei, Gang Wang, Xing Lu
This work reveals the significant advantages of high-temperature nitrogen (N) ion implantation for fabricating current-blocking layers (CBLs) in β-Ga2O3. A comparative investigation on the structural and electrical properties of N-implanted β-Ga2O3 was conducted under different implantation temperatures and post-implantation annealing (PIA) conditions. The results showed that the high-temperature implantation (HTI) at 500 °C, compared to the room-temperature implantation (RTI), introduced fewer structural defects and less lattice distortion to β-Ga2O3. The HTI-formed CBL demonstrated a far superior current-blocking capability than those formed by the RTI with/without a PIA, in terms of a much lower and more stable leakage current and a significantly enhanced breakdown voltage. Additionally, lateral MOSFETs fabricated with the HTI isolation exhibited a three orders of magnitude lower off-state leakage current while maintaining excellent on-state performance, compared to those using the isolation formed by RTI with PIA. These findings indicate that the in situ dynamic annealing effect of HTI effectively reduces implantation-induced damage, enhances impurity activation, and improves the overall performance of the N-implanted CBLs in β-Ga2O3.
{"title":"High-temperature N ion implantation for performance-enhanced current-blocking layers in β-Ga2O3","authors":"Yunjian Hu, Danni Su, Tiecheng Luo, Yuru Lai, Zhengyi Liao, Chunhong Zeng, Xiaodong Zhang, Man Hoi Wong, Zimin Chen, Yanli Pei, Gang Wang, Xing Lu","doi":"10.1063/5.0256968","DOIUrl":"https://doi.org/10.1063/5.0256968","url":null,"abstract":"This work reveals the significant advantages of high-temperature nitrogen (N) ion implantation for fabricating current-blocking layers (CBLs) in β-Ga2O3. A comparative investigation on the structural and electrical properties of N-implanted β-Ga2O3 was conducted under different implantation temperatures and post-implantation annealing (PIA) conditions. The results showed that the high-temperature implantation (HTI) at 500 °C, compared to the room-temperature implantation (RTI), introduced fewer structural defects and less lattice distortion to β-Ga2O3. The HTI-formed CBL demonstrated a far superior current-blocking capability than those formed by the RTI with/without a PIA, in terms of a much lower and more stable leakage current and a significantly enhanced breakdown voltage. Additionally, lateral MOSFETs fabricated with the HTI isolation exhibited a three orders of magnitude lower off-state leakage current while maintaining excellent on-state performance, compared to those using the isolation formed by RTI with PIA. These findings indicate that the in situ dynamic annealing effect of HTI effectively reduces implantation-induced damage, enhances impurity activation, and improves the overall performance of the N-implanted CBLs in β-Ga2O3.","PeriodicalId":8094,"journal":{"name":"Applied Physics Letters","volume":"218 1","pages":""},"PeriodicalIF":4.0,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143640059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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