ترغب بنشر مسار تعليمي؟ اضغط هنا

Coexistence of resistance oscillations and the anomalous metal phase in a lithium intercalated TiSe$_2$ superconductor

81   0   0.0 ( 0 )
 نشر من قبل Menghan Liao
 تاريخ النشر 2021
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

Superconductivity and charge density wave (CDW) appear in the phase diagram of a variety of materials including the high - $T$$_c$ cuprate family and many transition metal dichalcogenides (TMDs). Their interplay may give rise to exotic quantum phenomena. Here, we show that superconducting arrays can spontaneously form in TiSe$_2$ - a TMD with coexisting superconductivity and CDW - after lithium ion intercalation. We induce a superconducting dome in the phase diagram of Li$_x$TiSe$_2$ by using the ionic solid-state gating technique. Around optimal doping, we observe magnetoresistance oscillations, indicating the emergence of periodically arranged domains. In the same temperature, magnetic field and carrier density regime where the resistance oscillations occur, we observe signatures for the anomalous metal - a state with a resistance plateau across a wide temperature range below the superconducting transition. Our study not only sheds further insight into the mechanism for the periodic electronic structure, but also reveals the interplay between the anomalous metal and superconducting fluctuations.


قيم البحث

اقرأ أيضاً

New intercalation superconductors of Li$_x$(C$_2$H$_8$N$_2$)$_y$TiSe$_2$ and Li$_x$(C$_6$H$_{16}$N$_2$)$_y$TiSe$_2$ with $T_{rm c}$ = 4.2 K have successfully been synthesized via the co-intercalation of lithium and ethylenediamine or hexamethylenedia mine into 1T-TiSe$_2$. Moreover, it has been found that both intercalation compounds of Li$_x$TiSe$_2$ and (C$_2$H$_8$N$_2$)$_y$TiSe$_2$ also show superconductivity with $T_{rm c}$ = 2.4 K and 2.8 K, respectively. These results indicate that both the electron doping due to the intercalation of lithium and the expansion of the interlayer spacing between TiSe2 layers due to the intercalation of diamines suppress the charge density wave in 1T-TiSe$_2$, leading to the appearance of superconductivity.
We report a low-temperature scanning tunneling microscopy study of the charge density wave (CDW) order in 1$T$-TiSe$_2$ and Cu$_{0.08}$TiSe$_2$. In pristine 1$T$-TiSe$_2$ we observe a long-range coherent commensurate CDW (C-CDW) order. In contrast, C u$_{0.08}$TiSe$_{2}$ displays an incommensurate CDW (I-CDW) phase with localized C-CDW domains separated by domain walls. Density of states measurements indicate that the domain walls host an extra population of fermions near the Fermi level which may play a role in the emergence of superconductivity in this system. Fourier transform scanning tunneling spectroscopy studies suggest that the dominant mechanism for CDW formation in the I-CDW phase may be electron-phonon coupling.
The superconductivity and intercalation statein the lithium-and hexamethylenediamine (HMDA)-intercalated superconductor Li$_x$(C$_6$H$_{16}$N$_2$)$_y$Fe$_{2-z}$Se$_2$ have been investigated from powder x-ray diffraction, thermogravimetric and magneti c susceptibility measurements, changing the intercalation temperature, $T_i$, and the Li content, $x$. Both Li and HMDA have been co-intercalated stably up to $x$ = 2 roughly in the molar ratio of $x : y = 2 : 1$. In the case of $T_i$ = 45$^circ$C, it has been found that both Li and HMDA are co-intercalated locally at the edge of FeSe crystals, indicating that both Li and HMDA are hard to diffuse into the inside of FeSe crystals at 45$^circ$C. In the case of $T_i$ = 100$^circ$C, on the other hand, it has been found that both Li and HMDA diffuse into the inside of FeSe crystals, so that $T_c$ tends to increase with increasing $x$ from ~30 K at $x$ = 1 up to 38 K at $x$ = 2 owing to the increase of electron carriers doped from Li into the FeSe layers.
The type-II Dirac semimetal PdTe2 was recently reported to be a type-I superconductor with a superconducting transition temperature Tc = 1.65 K. However, the recent results from tunneling and point contact spectroscopy suggested the unusual state of a mixture of type-I and type-II superconductivity. These contradictory results mean that there is no clear picture of the superconducting phase diagram and warrants a detailed investigation of the superconducting phase. We report here the muon spin rotation and relaxation ($mu$SR) measurements on the superconducting state of the topological Dirac semimetal PdTe2. From $mu$SR measurements, we find that PdTe2 exhibits mixed type-I/type-II superconductivity. Using these results a phase diagram has been determined. In contrast to previous results where local type-II superconductivity persists up to Hc2 = 600 G, we observed that bulk superconductivity is destroyed above 225 G.
High-quality K(Fe$_{1-x}$Co$_x$)$_2$As$_2$ single crystals have been grown by using KAs flux method. Instead of increasing the superconducting transition temperature $T_{rm c}$ through electron doping, we find that Co impurities rapidly suppress $T_{ rm c}$ down to zero at only $x approx$ 0.04. Such an effective suppression of $T_{rm c}$ by impurities is quite different from that observed in Ba$_{0.5}$K$_{0.5}$Fe$_2$As$_2$ with multiple nodeless superconducting gaps. Thermal conductivity measurements in zero field show that the residual linear term $kappa_0/T$ only change slightly with $3.4%$ Co doping, despite the sharp increase of scattering rate. The implications of these anomalous impurity effects are discussed.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا