We present a systematical study on single crystalline FeSb2 using electrical transport and magnetic torque measurements at low temperatures. Nonlinear magnetic field dependence of Hall resistivity demonstrates a multi...We present a systematical study on single crystalline FeSb2 using electrical transport and magnetic torque measurements at low temperatures. Nonlinear magnetic field dependence of Hall resistivity demonstrates a multi-carrier transport instinct of the electronic transport. Current-controlled negative differential resistance(CC-NDR) observed in currentvoltage characteristics below ~ 7 K is closely associated with the intrinsic transition ~ 5 K of FeSb2, which is, however,mediated by extrinsic current-induced Joule heating effect. The antimony crystallized in a preferred orientation within the FeSb2 lattice in the high-temperature synthesis process leaves its fingerprint in the de Haas-Van Alphen(dHvA) oscillations, and results in the regular angular dependence of the oscillating frequencies. Nevertheless, possible existence of intrinsic non-trivial states cannot be completely ruled out. Our findings call for further theoretical and experimental studies to explore novel physics on flux-free grown FeSb_2 crystals.展开更多
By using angle-resolvea photoemission spectroscopy(ARPES) combined with the first-principies electronic structure calculations,we report the quantized states at the surface of a single crystal 2 H-TaSe_(2).We have obs...By using angle-resolvea photoemission spectroscopy(ARPES) combined with the first-principies electronic structure calculations,we report the quantized states at the surface of a single crystal 2 H-TaSe_(2).We have observed sub-bands of quantized states at the three-dimensional Brillouin zone center due to a highly dispersive band with light effective mass along k_(z) direction.The quantized sub-bands shift upward towards E_(F) while the bulk band at Γ shifts downward with the decrease of temperature across charge density wave(CDW) formation.The band shifts could be intimately related to the CDW.While neither the two-dimensional Fermi-surface nesting nor purely strong electron-phonon coupling can explain the mechanism of CDW in 2 H-TaSe_(2),our experiment may ignite the interest in understanding the CDW mechanism in this family.展开更多
We report the growth of ternary half-Heusler MnPtSn single crystals and detailed study on its structural and physical properties.MnPtSn single crystal has a larger lattice parameter than that in polycrystal and it exh...We report the growth of ternary half-Heusler MnPtSn single crystals and detailed study on its structural and physical properties.MnPtSn single crystal has a larger lattice parameter than that in polycrystal and it exhibits antiferromagnetism with transition temperature TN at about 215 K,distinctly different from the ferromagnetism of MnPtSn polycrystal.Hall resistivity measurement indicates that the dominant carriers are hole-type and the nearly temperature-independent carrier concentration reaches about 2.86×10^22 cm^-3 at 5 K.Moreover,the carrier mobility is also rather low(4.7 cm^2·V^-1s^-1 at 5 K).The above results strongly suggest that the significant Mn/Sn anti-site defects,i.e.,the content of Mn in MnPtSn single crystal,play a vital role on structural,magnetic and transport properties.展开更多
It was found that selenium doping can suppress the charge-density-wave(CDW) order and induce bulk superconductivity in ZrTe3. The observed superconducting dome suggests the existence of a CDW quantum critical point...It was found that selenium doping can suppress the charge-density-wave(CDW) order and induce bulk superconductivity in ZrTe3. The observed superconducting dome suggests the existence of a CDW quantum critical point(QCP) in ZrTe3-xSex near x ≈ 0.04. To elucidate the superconducting state near the CDW QCP, we measure the thermal conductivity of two ZrTe(3-x)Sex single crystals(x = 0.044 and 0.051) down to 80 m K. For both samples, the residual linear term κ0/T at zero field is negligible, which is a clear evidence for nodeless superconducting gap. Furthermore, the field dependence of κ0/T manifests a multigap behavior. These results demonstrate multiple nodeless superconducting gaps in ZrTe(3-x)Sex,which indicates conventional superconductivity despite of the existence of a CDW QCP.展开更多
基金supported by Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2016ZT06D348)the National Natural Science Foundation of China(Grant No.11874193)+1 种基金the Shenzhen Fundamental Subject Research Program,China(Grant Nos.JCYJ20170817110751776 and JCYJ20170307105434022)The work at Brookhaven is supported by the US Department of Energy,Office of Basic Energy Sciences as part of the Computational Material Science Program(material synthesis)
文摘We present a systematical study on single crystalline FeSb2 using electrical transport and magnetic torque measurements at low temperatures. Nonlinear magnetic field dependence of Hall resistivity demonstrates a multi-carrier transport instinct of the electronic transport. Current-controlled negative differential resistance(CC-NDR) observed in currentvoltage characteristics below ~ 7 K is closely associated with the intrinsic transition ~ 5 K of FeSb2, which is, however,mediated by extrinsic current-induced Joule heating effect. The antimony crystallized in a preferred orientation within the FeSb2 lattice in the high-temperature synthesis process leaves its fingerprint in the de Haas-Van Alphen(dHvA) oscillations, and results in the regular angular dependence of the oscillating frequencies. Nevertheless, possible existence of intrinsic non-trivial states cannot be completely ruled out. Our findings call for further theoretical and experimental studies to explore novel physics on flux-free grown FeSb_2 crystals.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11774421,11774424,11574394,11774423,11822412,and 11874047)the National Key R&D Program of China(Grant Nos.2016YFA0401002,2018YFA0307000,2016YFA0300504,and 2018FYA0305800)the Fundamental Research Funds for the Central Universities,China(Grant No.2042018kf-0030)。
文摘By using angle-resolvea photoemission spectroscopy(ARPES) combined with the first-principies electronic structure calculations,we report the quantized states at the surface of a single crystal 2 H-TaSe_(2).We have observed sub-bands of quantized states at the three-dimensional Brillouin zone center due to a highly dispersive band with light effective mass along k_(z) direction.The quantized sub-bands shift upward towards E_(F) while the bulk band at Γ shifts downward with the decrease of temperature across charge density wave(CDW) formation.The band shifts could be intimately related to the CDW.While neither the two-dimensional Fermi-surface nesting nor purely strong electron-phonon coupling can explain the mechanism of CDW in 2 H-TaSe_(2),our experiment may ignite the interest in understanding the CDW mechanism in this family.
基金Supported by the National Key R&D Program of China(Grant Nos.2018YFE0202600,2016YFA0300504)the National Natural Science Foundation of China(Nos.11574394,11774423,11822412)+2 种基金the Fundamental Research Funds for the Central Universitiesthe Research Funds of Renmin University of China(RUC)(Nos.15XNLQ07,18XNLG14,19XNLG17)the Office of Basic Energy Sciences,Materials Sciences and Engineering Division,U.S.Department of Energy(DOE)under Contract No.DE-SC0012704。
文摘We report the growth of ternary half-Heusler MnPtSn single crystals and detailed study on its structural and physical properties.MnPtSn single crystal has a larger lattice parameter than that in polycrystal and it exhibits antiferromagnetism with transition temperature TN at about 215 K,distinctly different from the ferromagnetism of MnPtSn polycrystal.Hall resistivity measurement indicates that the dominant carriers are hole-type and the nearly temperature-independent carrier concentration reaches about 2.86×10^22 cm^-3 at 5 K.Moreover,the carrier mobility is also rather low(4.7 cm^2·V^-1s^-1 at 5 K).The above results strongly suggest that the significant Mn/Sn anti-site defects,i.e.,the content of Mn in MnPtSn single crystal,play a vital role on structural,magnetic and transport properties.
基金Project supported by the National Basic Research Program of China(Grant Nos.2012CB821402 and 2015CB921401)the National Natural Science Foundation of China(Grant Nos.91421101,11422429,and 11204312)+1 种基金the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning,China,STCSM of China(Grant No.15XD1500200)Work at Brookhaven National Laboratory was supported by the US DOE under Contract No.DESC00112704
文摘It was found that selenium doping can suppress the charge-density-wave(CDW) order and induce bulk superconductivity in ZrTe3. The observed superconducting dome suggests the existence of a CDW quantum critical point(QCP) in ZrTe3-xSex near x ≈ 0.04. To elucidate the superconducting state near the CDW QCP, we measure the thermal conductivity of two ZrTe(3-x)Sex single crystals(x = 0.044 and 0.051) down to 80 m K. For both samples, the residual linear term κ0/T at zero field is negligible, which is a clear evidence for nodeless superconducting gap. Furthermore, the field dependence of κ0/T manifests a multigap behavior. These results demonstrate multiple nodeless superconducting gaps in ZrTe(3-x)Sex,which indicates conventional superconductivity despite of the existence of a CDW QCP.