38 research outputs found
Pressure-induced superconductivity in charge-density-wave compound LaTe2-xSbx (x=0 and 0.4)
Here, we have grown single crystals of LaTe2-xSbx (x=0 and 0.4) with
continuously adjustable CDW. High-pressure x-ray diffraction show LaTe2 does
not undergo phase transition and keep robust below 40 GPa. In-situ
high-pressure electrical measurements show LaTe2-xSbx undergo
semiconductor-metal-superconductivity transition at 4.6 and 2.5 GPa,
respectively. With the doping of Sb, the highest Tc increases from 4.6 to 6.5
K. Theoretical calculations reveal that the CDW has been completely suppressed
and the calculated Tc is about 2.97 K at 4.5 GPa, consistent with the measured
value. Then, the pressure-induced superconductivity in LaTe2-xSbx can be
explained in the framework of the BCS theory.Comment: 11 pages, 5 figure
Effects of Pressure and Doping on Ruddlesden-Popper phases Lan+1NinO3n+1
Recently the discovery of superconductivity with a critical temperature Tc up
to 80 K in Ruddlesden-Popper phases Lan+1NinO3n+1 (n = 2) under pressure has
garnered considerable attention. Up to now, the superconductivity was only
observed in La3Ni2O7 single crystal grown with the optical-image floating zone
furnace under oxygen pressure. It remains to be understood the effect of
chemical doping on superconducting La3Ni2O7 as well as other Ruddlesden-Popper
phases. Here, we systematically investigate the effect of external pressure and
chemical doping on polycrystalline Ruddlesden-Popper phases. Our results
demonstrate the application of pressure and doping effectively tunes the
transport properties of Ruddlesden-Popper phases. We find pressure-induced
superconductivity up to 86 K in La3Ni2O7 polycrystalline sample, while no
signatures of superconductivity are observed in La2NiO4 and La4Ni3O10 systems
under high pressure up to 50 GPa. Our study sheds light on the exploration of
high-Tc superconductivity in nickelates.Comment: 21 papes, 8 figures and 1 tabl
Effect of physical and chemical pressure on the superconductivity of caged-type quasiskutterudite Lu5Rh6Sn18
Lu5Rh6Sn18 is one of the caged-type quasiskutterudite superconductors with
superconducting transition temperature Tc = 4.12 K. Here, we investigate the
effect of pressure on the superconductivity in Lu5Rh6Sn18 by combining high
pressure electrical transport, synchrotron x-ray diffraction (XRD) and chemical
doping. Application of high pressure can enhance both the metallicity and the
superconducting transition temperature in Lu5Rh6Sn18. Tc is found to show a
continuous increase reaching up to 5.50 K at 11.4 GPa. Our high pressure
synchrotron XRD measurements demonstrate the stability of the pristine crystal
structure up to 12.0 GPa. In contrast, Tc is suppressed after the substitution
of La ions in Lu sites, inducing negative chemical pressure. Our study provides
valuable insights into the improvement of superconductivity in caged compounds.Comment: 9 pages, 8 figure
Pressure-tunable magnetic topological phases in magnetic topological insulator MnSb4Te7
Magnetic topological insulators, possessing both magnetic order and
topological electronic structure, provides an excellent platform to research
unusual physical properties. Here, we report a high-pressure study on the
anomalous Hall effect of magnetic TI MnSb4Te7 through transports measurements
combined with first-principle theoretical calculations. We discover that the
ground state of MnSb4Te7 experiences a magnetic phase transition from the
A-type antiferromagnetic state to ferromagnetic dominating state at 3.78 GPa,
although its crystal sustains a rhombohedral phase under high pressures up to 8
GPa. The anomalous Hall conductance {\sigma}xyA keeps around 10 {\Omega}-1
cm-1, dominated by the intrinsic mechanism even after the magnetic phase
transition. The results shed light on the intriguing magnetism in MnSb4Te7 and
pave the way for further studies of the relationship between topology and
magnetism in topological materials.Comment: 10 pages, 4 figure
Pressure induced superconductivity in WB2 and ReB2 through modifying the B layers
The recent discovery of superconductivity up to 32 K in the pressurized MoB2
reignites the interests in exploring high-Tc superconductors in
transition-metal diborides. Inspired by that work, we turn our attention to the
5d transition-metal diborides. Here we systematically investigate the responses
of both structural and physical properties of WB2 and ReB2 to external
pressure, which possess different types of boron layers. Similar to MoB2, the
pressure-induced superconductivity was also observed in WB2 above 60 GPa with a
maximum Tc of 15 K at 100 GPa, while no superconductivity was detected in ReB2
in this pressure range. Interestingly, the structures at ambient pressure for
both WB2 and ReB2 persist to high pressure without structural phase
transitions. Theoretical calculations suggest that the ratio of flat boron
layers in this class of transition-metal diborides may be crucial for the
appearance of high Tc. The combined theoretical and experimental results
highlight the effect of geometry of boron layers on superconductivity and shed
light on the exploration of novel high-Tc superconductors in borides.Comment: 17 pages,5 figure
Pressure-induced Superconductivity and Structure Phase Transition in SnAs-based Zintl Compound SrSn2As2
Layered SnAs-based Zintl compounds exhibit a distinctive electronic
structure, igniting extensive research efforts in areas of superconductivity,
topological insulators and quantum magnetism. In this paper, we systematically
investigate the crystal structures and electronic properties of the Zintl
compound SrSn2As2 under high-pressure. At approximately 20.8 GPa,
pressure-induced superconductivity is observed in SrSn2As2 with a
characteristic dome-like evolution of Tc. Theoretical calculations together
with high pressure synchrotron X-ray diffraction and Raman spectroscopy have
identified that SrSn2As2 undergoes a structural transformation from a trigonal
to a monoclinic structure. Beyond 28.3 GPa, the superconducting transition
temperature is suppressed due to a reduction of the density of state at the
Fermi level. The discovery of pressure-induced superconductivity, accompanied
by structural transitions in SrSn2As2, greatly expands the physical properties
of layered SnAs-based compounds and provides a new ground states upon
compression.Comment: 15 pages, 6 figures. arXiv admin note: text overlap with
arXiv:2307.1562
Robust anomalous Hall effect in ferromagnetic metal under high pressure
Recently, the giant intrinsic anomalous Hall effect (AHE) has been observed
in the materials with kagome lattice. In this study, we systematically
investigate the influence of high pressure on the AHE in the ferromagnet
LiMn6Sn6 with clean Mn kagome lattice. Our in-situ high-pressure Raman
spectroscopy indicates that the crystal structure of LiMn6Sn6 maintains a
hexagonal phase under high pressures up to 8.51 GPa. The anomalous Hall
conductivity (AHC) {\sigma}xyA remains around 150 {\Omega}-1 cm-1, dominated by
the intrinsic mechanism. Combined with theoretical calculations, our results
indicate that the stable AHE under pressure in LiMn6Sn6 originates from the
robust electronic and magnetic structure.Comment: 11 pages 5 figure
Pressure-induced Superconductivity in Zintl Topological Insulator SrIn2As2
The Zintl compound AIn2X2 (A = Ca, Sr, and X = P, As), as a theoretically
predicted new non-magnetic topological insulator, requires experiments to
understand their electronic structure and topological characteristics. In this
paper, we systematically investigate the crystal structures and electronic
properties of the Zintl compound SrIn2As2 under both ambient and high-pressure
conditions. Based on systematic angle-resolved photoemission spectroscopy
(ARPES) measurements, we observed the topological surface states on its (001)
surface as predicted by calculations, indicating that SrIn2As2 is a strong
topological insulator. Interestingly, application of pressure effectively tuned
the crystal structure and electronic properties of SrIn2As2. Superconductivity
is observed in SrIn2As2 for pressure where the temperature dependence of the
resistivity changes from a semiconducting-like behavior to that of a metal. The
observation of nontrivial topological states and pressure-induced
superconductivity in SrIn2As2 provides crucial insights into the relationship
between topology and superconductivity, as well as stimulates further studies
of superconductivity in topological materials.Comment: 15 pages,5 figure