Zhongxian Zhao

Shanghai Institute of Applied Physics, Shanghai, Shanghai Shi, China

Are you Zhongxian Zhao?

Claim your profile

Publications (101)191.12 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The central depression of the Qiongdongnan Basin can be divided into the eastern and western sub-basins by the Lingshui–Songnan paleo-uplift. To the northwest, the orientation of the faults turns from NE, to EW, and later to NW; In the southwest, the orientation of the faults turns from NE, to NNE, and then to NW, making the central depression much wider towards the west. In the eastern sub-basin, the NE-striking faults and the EW-striking faults made up an echelon, making the central depression turn wider towards the east. Fault activity rates indicate that faulting spreads gradually from both the east and west sides to the middle of the basin. Hence, extensional stress in the eastern sub-basin may be related to the South China Sea spreading system, whereas the western sub-basin was more under the effect of the activity of the Red River Fault. The extreme crustal stretching in the eastern sub-basin was probably related to magmatic setting. It seems that there are three periods of magmatic events that occurred in the eastern sub-basin. In the eastern part of the southern depression, the deformed strata indicate that the magma may have intruded into the strata along faults around T60 (23.3 Ma). The second magmatic event occurred earlier than 10.5 Ma, which induced the accelerated subsidence. The final magmatic event commenced later than 10 Ma, which led to today’s high heat flow. As for the western sub-basin, the crust thickened southward, and there seemed to be a southeastward lower crustal flow, which happened during continental breakup which was possibly superimposed by a later lower crustal flow induced by the isostatic compensation of massive sedimentation caused by the right lateral slipping of the Red River Fault. Under the huge thick sediment, super pressure developed in the western sub-basin. In summary, the eastern sub-basin was mainly affected by the South China Sea spreading system and a magma setting, whereas the western sub-basin had a closer relationship with the Indo-China extrusion system.
    Marine Geophysical Researches 12/2014; · 1.06 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Qiongdongnan Basin (QB) experienced three main tectonic stages in the Cenozoic: rifting, thermal subsidence, and accelerated subsidence. Corresponding to these stages, the slope breaks also underwent three different evolutionary stages, which differed in space and time between the east and west of QB. Structural slope breaks developed during the rifting stage in the Paleocene. Transitional sedimentary strata without obvious slope break developed in the neritic environment during the thermal subsidence stage in the Neocene. Sedimentary slope breaks and gentle slope zone without slope break developed during the accelerated subsidence stage. The sedimentary slope breaks could be further classified into progradational and aggradational types, the starting points of which varied in space and time. Spatially, the progradational sequences in the Ledong and Lingshui sags started at the north of today’s deep central basin, distant from the basin edge. In the Songnan and Baodao sags, the aggradational sequences were close to the sag edge and essentially controlled by the underlying major boundary faults. Temporally, sedimentary slope breaks developed early in the east and late in the west and were initially partitioned and eventually unified. Fault activity controlled the types and ending time of structural slope breaks during the rifting stage, while tectonic subsidence controlled the time and places of progradational slope breaks during the accelerated subsidence stage. Sediment supply controlled the superposition patterns of the sedimentary sequences of the sedimentary slope breaks. It is suggested that the evolutionary history of the slope breaks has been primarily affected by the southward transition of the South China Sea ocean ridge, the westward collision of the Philippine Sea Plate, and the dextral strike-slipping of the Red River Fault.
    Marine Geophysical Researches 12/2014; · 1.06 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Theory predicts that three-dimensional Dirac semimetals (3D-DSMs) can be turned into a variety of novel quantum phases by tuning control parameters to break either time reversal symmetry or inversion symmetry. Pressure is one such parameter, and can manipulate electronic and crystal structures without changing the chemistry. Here, we report the first observation of a pressure-induced breakdown of the 3D-DSM state in Cd3As2. In-situ synchrotron X-ray and single crystal resistance measurements find that Cd3As2 undergoes a structural phase transition from a metallic tetragonal phase to a semiconducting high pressure phase at 2.57 GPa; the phase transition breaks the semimetal state. Applying pressure around the phase transition, we observe unusual physical phenomena, including dramatic changes in mobility, Hall resistance and magnetoresistance in addition to the gap opening, which demonstrate the breakdown of the 3D-DSM state. Furthermore, an intermediate state found near the boundary of the phase transition appears to signify the emergence of a novel quantum phase between the low pressure and high pressure phases.
    10/2014;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A unique platform for investigating the correlation between the antiferromagnetic (AFM) and superconducting (SC) states in high temperature superconductors is created by the discovery of alkaline iron selenide superconductors which are composed of an AFM insulating phase and a SC phase separated spatially. Our previous studies showed that pressure can fully suppress the superconductivity of ambient-pressure superconducting phase (SC-I) and AFM order simultaneously, then induce another superconducting phase (SC-II) at higher pressure. Consequently, the connection between the two superconducting phases becomes an intriguing issue. In this study, on the basis of observing pressure-induced reemergence of superconductivity in Rb0.8Fe2-ySe2-xTex (x=0, 0.19 and 0.28) superconductors, we find that the superconductivity of the SC-I and SC-II phases as well as the AFM ordered state can be synchronously tuned by Te doping and disappear together at the doping level of x=0.4. We propose that the two superconducting phases are connected by the AFM phase, in other words, the state of long-ranged AFM order plays a role in giving rise to superconductivity of the SC-I phase, while the fluctuation state of the suppressed AFM phase drives the emergence of SC-II phase. These results comprehensively demonstrate the versatile roles of AFM states in stabilizing and developing superconductivity in the alkaline iron selenide superconductors.
    07/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: The Qiongdongnan Basin, located off Hainan Island, South China, is a petroliferous basin containing what is currently the largest offshore-producing gas field in China (YA13–1). This paper evaluated the potential of CO2 storage in the Qiongdongnan Basin to provide background data on CO2 storage capacities for regional planning purposes. Four regional seals and high-quality reservoirs exists in the basin, in mostly marine sequences. The estimated mean effective CO2 storage capacity of the basin is 41 GtCO2, determined from published data and the Carbon Sequestration Leadership Forum methodology for assessing oil and gas storage capacity; the majority of the storage capacity is in saline formations and oil and gas field (15 MtCO2 and 832 MtCO2, respectively). The prospective areas for CO2 storage in the Qiongdongnan Basin are in the belts of the Northern Depression and the Central Uplift. The Yacheng Uplift, as the most favorable area for CO2 storage, contains the YA13–1 gas field, which has an estimated mean effective CO2 storage capacity of 73 MtCO2. The Qiongdongnan Basin may provide storage sites for CO2 stripped from the CO2-enriched gas from the basin itself, or from the emission sources in Hong Kong and Guangdong Province. However, industrial development on Hainan Island is weak, as the island was defined as an ‘island for international tourism’ by the Chinese government in 2009. The feasibility of transporting CO2 to storage sites in the Qiongdongnan Basin using the pipeline now transporting gas from the YA13–1 gas field to Hong Kong should be explored.
    Greenhouse Gases: Science and Technology 05/2014; · 2.68 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Here, we report that K-doped BaMn2Bi2 shows no experimental evidence of superconductivity down to 1.5 K under pressures up to 35.6 GPa, however, a tetragonal to an orthorhombic phase transition is observed at pressure of 20 GPa. Theoretical calculations for the tetragonal and orthorhombic phases, on basis of our high-pressure XRD data, find that the AFM order is robust in both of the phases in pressurized Ba0.61K0.39Mn2Bi2. Our experimental and theoretical results suggest that the K-doped BaMn2Bi2 belongs to a strong Hunds AFM metal with a hybridization of localized spin electrons and itinerant electrons, and that its robust AFM order essentially prevents the emergence of superconductivity.
    Scientific reports. 04/2014; 4.
  • [Show abstract] [Hide abstract]
    ABSTRACT: Here, we report that K-doped BaMn2Bi2 shows no experimental evidence of superconductivity down to 1.5 K under pressures up to 35.6 GPa, however, a tetragonal to an orthorhombic phase transition is observed at pressure of 20 GPa. Theoretical calculations for the tetragonal and orthorhombic phases, on basis of our high-pressure XRD data, find that the AFM order is robust in both of the phases in pressurized Ba0.61K0.39Mn2Bi2. Our experimental and theoretical results suggest that the K-doped BaMn2Bi2 belongs to a strong Hunds AFM metal with a hybridization of localized spin electrons and itinerant electrons, and that its robust AFM order essentially prevents the emergence of superconductivity.
    03/2014;
  • [Show abstract] [Hide abstract]
    ABSTRACT: There is considerable interest in uncovering the physics of iron-based superconductivity from the alkaline iron selenides, a materials class containing an insulating phase (245 phase) and a superconducting (SC) phase. Due to the microstructural complexity of these superconductors, the role of the 245 phase in the development of the superconductivity has been a puzzle. Here we demonstrate a comprehensive high-pressure study on the insulating samples with pure 245 phase and biphasic SC samples. We find that the insulating behavior can be completely suppressed by pressure in the insulating samples and also identify an intermediate metallic (M') state. The Mott insulating (MI) state of the 245 phase and the M' state coexist over a significant range of pressure up to ̃10 GPa, the same pressure at which the superconductivity of the SC samples vanishes. Our results reveal the M' state as a pathway that connects the insulating and SC phases of the alkaline iron selenides and indicate that the coexistence and interplay between the MI and M' states is a necessary condition for superconductivity. Finally, we interpret the M' state in terms of an orbital selectivity of the correlated 3d electrons.
    02/2014; 89(9).
  • [Show abstract] [Hide abstract]
    ABSTRACT: Pressure-induced superconductivity is oberserved in Ca10 (Pt3 As8 )(Fe2 As2 )5 by in situ high-pressure resistance and magnetic susceptibility measurements. Scaling of the pressure-induced and doping-induced superconductivity shows that the electronic phase diagrams of the pressurized and chemically doped 10-3-8 compound are similar in the moderate pressure and doping range but are disparate at higher pressure and heavy doping.
    Advanced Materials 01/2014; · 14.83 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Post-rift fault activities were often observed in deepwater basins, which have great contributions to oil and gas migration and accumulation. The main causes for post-rift fault activities include tectonic events, mud or salt diapirs, and gravitational collapse. In the South China Sea continental margin, post-rift fault activities are widely distributed, especially in Baiyun sag, one of the largest deepwater sag with its main body located beneath present continental slope. During the post-rift stage, large population of faults kept active for a long time from 32 Ma (T70) till 5.5 Ma (T10). Seismic interpretation, fault analysis and analogue modeling experiments indicate that the post-rift fault activities in Baiyun sag between 32 Ma (T70) and 13.8 Ma (T30) was mainly controlled by gravity pointing to the Main Baiyun sag, which caused the faults extensive on the side facing Main Baiyun sag and the back side compressive. Around 32 Ma (T70), the breakup of the continental margin and the spreading of the South China Sea shed a combined effect of weak compression toward Baiyun sag. The gravity during post-rift stage might be caused by discrepant subsidence and sedimentation between strongly thinned sag center and wing areas. This is supported by positive relationship between sedimentation rate and fault growth index. After 13.8 Ma (T30), fault activity shows negative relationship with sedimentation rate. Compressive uplift and erosion in seismic profiles as well as negative tectonic subsiding rates suggest that the fault activity from 13.8 Ma (T30) to 5.5 Ma (T10) might be controlled by the subductive compression from the Philippine plate in the east.
    Journal of Asian Earth Sciences. 01/2014; 89:76–87.
  • [Show abstract] [Hide abstract]
    ABSTRACT: A 1-D unloaded tectonic subsidence (air-loaded tectonic subsidence) model is proposed and applied to the Qiongdongnan Basin. Results show that three episodes of subsidence exist in Cenozoic, that is, syn-rift rapid subsidence (Eocene-Oligocene) with subsidence rate at 20-100 m/m.y., post-rift slow thermal subsidence (early-middle Miocene) around 40 m/m.y., and post-rift accelerated subsidence (since late Miocene) 40-140 m/m.y., which is substantially deviated from the exponentially decayed thermal subsidence model. For exploring the mechanism of post-rift accelerated subsidence, the faulting analyses are conducted and results show that there is a dramatically decrease in the numbers of active faults and fault growth rate since 21 Ma, which indicates that no active brittle crust extension occurred during post-rift period. Furthermore, previous studies have demonstrated that the stretching of the upper crust is far less than that affecting the whole crust. Therefore, we infer that the lower crust thinned during the post-rift period and a new model of basin development and evolution is put forward to explain the post-rift accelerated subsidence and depth-dependent crust thinning in the Qiongdongnan Basin, which is supported by gravity data.
    Marine Geophysical Researches 11/2013; 34(3-4). · 1.06 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The emergence of superconductivity in the iron pnictide or cuprate high temperature superconductors usually accompanies the suppression of a long-ranged antiferromagnetic (AFM) order state in a corresponding parent compound by doping or pressurizing. A great deal of effort by doping has been made to find superconductivity in Mn-based compounds, which are thought to bridge the gap between the two families of high temperature superconductors, but the AFM order was not successfully suppressed. Here we report the first observations of the pressure-induced elimination of long-ranged AFM order at ~ 34 GPa and a crossover from an AFM insulating to an AFM metallic state at ~ 20 GPa in LaMnPO single crystals that are iso-structural to the LaFeAsO superconductor by in-situ high pressure resistance and ac susceptibility measurements. These findings are of importance to explore potential superconductivity in Mn-based compounds and to shed new light on the underlying mechanism of high temperature superconductivity.
    Scientific Reports 08/2013; 3:2555. · 5.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Ca10(PtnAs8)(Fe2As2)5 (n=3,4) compounds are a new type of iron pnictide superconductor whose structures consist of stacking Ca-PtnAs8-Ca-Fe2As2 layers in a unit cell. When n=3 (the 10-3-8 phase), the undoped compound is an antiferromagnetic (AFM) semiconductor, while, when n=4 (the 10-4-8 phase), the undoped compound is a superconductor (Tc=26K), a difference that has been attributed to the electronic character of the PtnAs8 intermediary layers. Here we report high-pressure studies on 10-3-8 and 10-4-8, using a combination of in-situ resistance, magnetic susceptibility, Hall coefficient and X-ray diffraction measurements. We find that the AFM order in undoped 10-3-8 is suppressed completely at 3.5 GPa and that superconductivity then appears in the 3.5-7 GPa pressure range with a classic dome-like behavior. In contrast, Tc in the 10-4-8 phase displays a monotonic decrease with increasing pressure. Our results allow for the establishment of a unique correspondence between pressure-induced and doping-induced superconductivity in the high-Tc iron pnictides, and also points the way to an effective strategy for finding new high-Tc superconductors.
    01/2013;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Here we show that a pressure of about 8 GPa suppresses both the vacancy order and the insulating phase, and a further increase of the pressure to about 18 GPa induces a second transition or crossover. No superconductivity has been found in compressed insulating 245 phase. The metallic phase in the intermediate pressure range has a distinct behavior in the transport property, which is also observed in the superconducting sample. We interpret this intermediate metal as an orbital selective Mott phase (OSMP). Our results suggest that the OSMP provides the physical pathway connecting the insulating and superconducting phases of these iron selenide materials.
    09/2012;
  • Zhongxian Zhao, Xiaoli Dong, Liling Sun
    [Show abstract] [Hide abstract]
    ABSTRACT: We highlight a few points on iron-based superconductors in this paper. Experimental evidence for intrinsic inhomogeneity and phase separation in Fe-based superconductors is reviewed first. The non-BCS feature and other similarities between the Fe-based superconductors and the cuprates are also presented. The pressure effect on the FeSe-based superconductors observed recently is then discussed in terms of the interplay between superconducting transition temperature and structural characters. It is suggested that there is room for exploring new superconductors with higher transition temperature and that the improvement on the sample quality is necessary for further investigation on the superconducting mechanism.
    Solid State Communications 04/2012; 152(8):660–665. · 1.53 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Pressure has an essential role in the production and control of superconductivity in iron-based superconductors. Substitution of a large cation by a smaller rare-earth ion to simulate the pressure effect has raised the superconducting transition temperature T(c) to a record high of 55 K in these materials. In the same way as T(c) exhibits a bell-shaped curve of dependence on chemical doping, pressure-tuned T(c) typically drops monotonically after passing the optimal pressure. Here we report that in the superconducting iron chalcogenides, a second superconducting phase suddenly re-emerges above 11.5 GPa, after the T(c) drops from the first maximum of 32 K at 1 GPa. The T(c) of the re-emerging superconducting phase is considerably higher than the first maximum, reaching 48.0-48.7 K for Tl(0.6)Rb(0.4)Fe(1.67)Se(2), K(0.8)Fe(1.7)Se(2) and K(0.8)Fe(1.78)Se(2).
    Nature 03/2012; 483(7387):67-9. · 38.60 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this talk, we present our recent progress in effect of pressure on superconductivity of newly discovered iron chalcogenide superconductors. We show that the either positive or negative pressure can tune superconductivity of this new kind of superconductors. Superconductivity with higher superconducting transition temperature Tc can reemerge after elimination of the initial superconducting phase upon compression. We find that the maximum Tc of the reemerging superconducting phase is as high as 48.7 K for K0.8Fe1.70Se2 and 48 K for Tl0.6Rb0.4Fe1.67Se2, setting a new Tc record for chalcogenide superconductors. The presence of the second superconducting phase is proposed to be related to pressure-induced quantum criticality. Our findings open up the potential route for the exploration of high-Tc superconductivity in iron-based and other superconductors.
    02/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Pressure plays an essential role in the induction1 and control2,3 of superconductivity in iron-based superconductors. Substitution of a smaller rare-earth ion for the bigger one to simulate the pressure effects has surprisingly raised the superconducting transition temperature Tc to the record high 55 K in these materials4,5. However, Tc always goes down after passing through a maximum at some pressure and the superconductivity eventually tends to disappear at sufficiently high pressures1-3. Here we show that the superconductivity can reemerge with a much higher Tc after its destruction upon compression from the ambient-condition value of around 31 K in newly discovered iron chalcogenide superconductors. We find that in the second superconducting phase the maximum Tc is as high as 48.7 K for K0.8Fe1.70Se2 and 48 K for (Tl0.6Rb0.4)Fe1.67Se2, setting the new Tc record in chalcogenide superconductors. The presence of the second superconducting phase is proposed to be related to pressure-induced quantum criticality. Our findings point to the potential route to the further achievement of high-Tc superconductivity in iron-based and other superconductors.
    10/2011;
  • Jie Liao, Di Zhou, ZhongXian Zhao, YunFan Zhang, ZiYing Xu
    [Show abstract] [Hide abstract]
    ABSTRACT: The Baiyun Sag is the deepest sag in the Pearl River Mouth Basin in northern continental margin of South China Sea, with the maximum sediment thickness over 12.5 km above the basement including >6.5 km sediments above the 30 Ma breakup unconformity. According to the theoretical models for the rifted basins, the post-rift subsidence is driven solely by the thermal contraction and can be calculated as the function of the lithospheric stretching factor. A method combining the forward modeling and reverse backstripping was designed to estimate lithospheric stretching factor. Using the 2D forward modeling based on the flexural cantilever model, we simulated the multi-rifting process of the Baiyun Sag with constrain of the backstripped profiles. By doing this the lithospheric stretching factor was obtained, and then the theoretical post-rift subsidence was calculated. The calculated theoretical subsidence was much smaller than the observed subsidence given by backstripping. Along the 1530 line in the Baiyun Sag, the anomalous post-rift subsidence is over 2 km in the sag center, and varies slightly to the north and south edges of the sag. This suggests that the anomalous post-rift subsidence continues beyond the sag both in the continental shelf to the north and in the continental slope to the south. The sensitivity tests in the forward modeling process indicate that only the use of low-angle faults (⩽13°) can we simulate the shape of the backstripped profile.
    Science China Earth Science 08/2011; · 1.26 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report the first experimental evidence for the intimate connection between superconductivity and antiferromagnetism in Rb0.8Fe2Se2-xTex single crystal under negative chemical pressure by substituting Se with isovalent Te atoms. Electrical resistance measurements in the temperature range from 4 K to 550 K demonstrate that both superconducting transition temperature (Tc) and Neel temperature (TN) were suppressed continuously with the lattice expansion. When the Te concentration x in Rb0.8Fe2Se2-xTex approaches 0.3, the superconducting transition temperature Tc is completely suppressed and the sample behaves like a semiconductor, meanwhile the characteristic peak of antiferromagnetic transition on resistance curve disappears. Our observation suggests that the pressure-induced lattice expansion can be used to tune the correlativity of superconductivity and antiferromagnetism.
    Physical review. B, Condensed matter 07/2011; · 3.77 Impact Factor

Publication Stats

612 Citations
191.12 Total Impact Points

Institutions

  • 2014
    • Shanghai Institute of Applied Physics
      Shanghai, Shanghai Shi, China
  • 2001–2014
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 1991–2014
    • Chinese Academy of Sciences
      • • Key Laboratory of Marginal Sea Geology
      • • Institute of Physics
      Peping, Beijing, China
  • 1988–2013
    • Northeast Institute of Geography and Agroecology
      • • Institute of Physics
      • • Key Laboratory of Marginal Sea Geology
      • • Condensed Matter Physics
      • • Institute of Chemistry
      Beijing, Beijing Shi, China
  • 2009
    • University of Tennessee
      • Department of Physics & Astronomy
      Knoxville, TN, United States
  • 2008
    • University of Houston
      • Texas Center for Superconductivity
      Houston, TX, United States
  • 1998
    • Institute of physics china
      Peping, Beijing, China
  • 1996
    • Hefei Institute of Physical Sciences, Chinese Academy of Sciences
      Luchow, Anhui Sheng, China