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H Ding - One of the best experts on this subject based on the ideXlab platform.
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two Pseudogaps with different energy scales at the antinode of the high temperature bi2sr2cuo6 superconductor using angle resolved photoemission spectroscopy
Physical Review B, 2011Co-Authors: Keiichi I Nakayama, H Ding, T Sato, Z H Pan, P Richard, Haihu Wen, Kazutaka Kudo, Takahiko SasakiAbstract:We performed high-resolution angle-resolved photoemission spectroscopy on single-layered cuprate Bi2Sr2CuO6 to clarify the origin of the Pseudogap. By using various photon energies, we succeeded in directly observing two different Pseudogaps with two different energy scales which coexist in the antinodal region: one reflects the d(x2-y2)-wave pairing strength while the other has a larger energy scale suggesting an origin distinct from superconductivity. The observed two-Pseudogap behavior provides a key to fully understanding the Pseudogap phenomena in cuprates.
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two Pseudogaps with different energy scales at the antinode of the high temperature bi2sr2cuo6 superconductor using angle resolved photoemission spectroscopy
Physical Review B, 2011Co-Authors: K. Nakayama, H Ding, T Sato, P Richard, Haihu Wen, Kazutaka Kudo, Zhihui Pan, Takahiko SasakiAbstract:We performed high-resolution angle-resolved photoemission spectroscopy on single-layered cuprate Bi${}_{2}$Sr${}_{2}$CuO${}_{6}$ to clarify the origin of the Pseudogap. By using various photon energies, we succeeded in directly observing two different Pseudogaps with two different energy scales which coexist in the antinodal region: one reflects the ${d}_{{x}^{2}\ensuremath{-}{y}^{2}}$-wave pairing strength while the other has a larger energy scale suggesting an origin distinct from superconductivity. The observed two-Pseudogap behavior provides a key to fully understanding the Pseudogap phenomena in cuprates.
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destruction of the fermi surface in underdoped high t c superconductors
Nature, 1998Co-Authors: Michael R Norman, H Ding, Tsunehiro Takeuchi, Mohit Randeria, Juan Carlos Campuzano, T Yokoya, T Takahashi, Takashi MochikuAbstract:The Fermi surface—the set of points in momentum space describing gapless electronic excitations—is a central concept in the theory of metals. In this context, the normal ‘metallic’ state of the optimally doped high-temperature superconductors is not very unusual: above the superconducting transition temperature, Tc, there is evidence for a large Fermi surface1,2,3, despite the absence of well-defined elementary excitations. In contrast, the normal state of underdoped high-temperature superconductors differs in that there is evidence for a ‘Pseudogap’ above Tc (4–7). Here we examine, using angle-resolved photoemission spectroscopy, the temperature dependence of the Fermi surface in underdoped Bi2Sr2CaCu2O8+δ. We find that, on cooling the sample, the Pseudogap opens up at different temperatures for different points in momentum space. This leads to an initial breakup of the Fermi surface, at a temperature T*, into disconnected arcs, which then shrink with decreasing temperature before collapsing to the point nodes of the superconducting ground state below Tc. This unusual behaviour, where the Fermi surface does not form a continuous contour in momentum space as in conventional metals, is unprecedented in that it occurs in the absence of long-range order. Moreover, although the superconducting gap below Tc evolves smoothly into the Pseudogap above Tc, the Pseudogap differs in its unusual temperature-dependent anisotropy, implying an intimate but non-trivial relationship between the Pseudogap and the superconducting gap.
Tsunehiro Takeuchi - One of the best experts on this subject based on the ideXlab platform.
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Visualization of the interplay between high-temperature superconductivity, the Pseudogap and impurity resonances
Nature Physics, 2008Co-Authors: Kamalesh Chatterjee, W D Wise, Michael Boyer, Takeshi Kondo, Tsunehiro Takeuchi, Hiroshi Ikuta, Eric HudsonAbstract:Visualization of the interplay between high-temperature superconductivity, the Pseudogap and impurity resonances
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interpretation of the hume rothery rule in complex electron compounds γ phase cu5zn8 alloy fk type al30mg40zn30 and mi type al68cu7ru17si8 1 1 1 1 1 1 approximants
Progress in Materials Science, 2004Co-Authors: Uichiro Mizutani, Tsunehiro Takeuchi, H SatoAbstract:The Hume–Rothery matching rule 2kF=Khkl has been theoretically investigated by performing the LMTO-ASA (Linear Muffin-Tin Orbital–Atomic Sphere Approximation) band calculations for the three electron compounds: the γ-phase Cu5Zn8 compound or γ-brass, the nearly-free-electron-like Frank–Kasper-type Al30Mg40Zn30 1/1–1/1–1/1 approximant and the Mackay–Icosahedral-type Al68Cu7Ru17Si8 1/1–1/1–1/1 approximant. The zone planes responsible for the formation of the Pseudogap across the Fermi level are identified. In the free-electron-like Al–Mg–Zn approximant, the Fermi surface-Brillouin zone interaction participating in the Hume-Rothery matching rule solely gives rise to a sizable Pseudogap at the Fermi level. In the case of the γ-brass and the Al–Cu–Ru–Si approximant, where d-states are involved in the middle of the valence band, we could demonstrate that the particular Fermi surface-Brillouin zone interactions are strongly coupled with the sp-d hybridization to produce a deep Pseudogap across the Fermi level.
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destruction of the fermi surface in underdoped high t c superconductors
Nature, 1998Co-Authors: Michael R Norman, H Ding, Tsunehiro Takeuchi, Mohit Randeria, Juan Carlos Campuzano, T Yokoya, T Takahashi, Takashi MochikuAbstract:The Fermi surface—the set of points in momentum space describing gapless electronic excitations—is a central concept in the theory of metals. In this context, the normal ‘metallic’ state of the optimally doped high-temperature superconductors is not very unusual: above the superconducting transition temperature, Tc, there is evidence for a large Fermi surface1,2,3, despite the absence of well-defined elementary excitations. In contrast, the normal state of underdoped high-temperature superconductors differs in that there is evidence for a ‘Pseudogap’ above Tc (4–7). Here we examine, using angle-resolved photoemission spectroscopy, the temperature dependence of the Fermi surface in underdoped Bi2Sr2CaCu2O8+δ. We find that, on cooling the sample, the Pseudogap opens up at different temperatures for different points in momentum space. This leads to an initial breakup of the Fermi surface, at a temperature T*, into disconnected arcs, which then shrink with decreasing temperature before collapsing to the point nodes of the superconducting ground state below Tc. This unusual behaviour, where the Fermi surface does not form a continuous contour in momentum space as in conventional metals, is unprecedented in that it occurs in the absence of long-range order. Moreover, although the superconducting gap below Tc evolves smoothly into the Pseudogap above Tc, the Pseudogap differs in its unusual temperature-dependent anisotropy, implying an intimate but non-trivial relationship between the Pseudogap and the superconducting gap.
S. Badoux - One of the best experts on this subject based on the ideXlab platform.
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giant thermal hall conductivity in the Pseudogap phase of cuprate superconductors
Bulletin of the American Physical Society, 2020Co-Authors: Gael Grissonnanche, Adrien Gourgout, Francis Laliberte, S. Badoux, Jianshi Zhou, Anaelle Legros, Etienne Lefrancois, Victor Zatko, M Lizaire, S PyonAbstract:The nature of the Pseudogap phase of the copper oxides (‘cuprates’) remains a puzzle. Although there are indications that this phase breaks various symmetries, there is no consensus on its fundamental nature1. Fermi-surface, transport and thermodynamic signatures of the Pseudogap phase are reminiscent of a transition into a phase with antiferromagnetic order, but evidence for an associated long-range magnetic order is still lacking2. Here we report measurements of the thermal Hall conductivity (in the x–y plane, κxy) in the normal state of four different cuprates—La1.6−xNd0.4SrxCuO4, La1.8−xEu0.2SrxCuO4, La2−xSrxCuO4 and Bi2Sr2−xLaxCuO6+δ. We show that a large negative κxy signal is a property of the Pseudogap phase, appearing at its critical hole doping, p*. It is also a property of the Mott insulator at p ≈ 0, where κxy has the largest reported magnitude of any insulator so far3. Because this negative κxy signal grows as the system becomes increasingly insulating electrically, it cannot be attributed to conventional mobile charge carriers. Nor is it due to magnons, because it exists in the absence of magnetic order. Our observation is reminiscent of the thermal Hall conductivity of insulators with spin-liquid states4–6, pointing to neutral excitations with spin chirality7 in the Pseudogap phase of cuprates. The so-called Pseudogap phase in hole-doped cuprate superconductors is associated with an unusually large thermal Hall effect that attains unprecedented levels as the parent Mott insulator is approached.
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wiedemann franz law and abrupt change in conductivity across the Pseudogap critical point of a cuprate superconductor
arXiv: Superconductivity, 2018Co-Authors: Adrien Gourgout, Amirreza Ataei, Francis Laliberte, S. Badoux, B Michon, Patrick Bourgeoishope, Clement Collignon, Jianshi Zhou, N DoironleyraudAbstract:The thermal conductivity $\kappa$ of the cuprate superconductor La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ was measured down to 50 mK in seven crystals with doping from $p=0.12$ to $p=0.24$, both in the superconducting state and in the magnetic field-induced normal state. We obtain the electronic residual linear term $\kappa_0/T$ as $T \to 0$ across the Pseudogap critical point $p^{\star}= 0.23$. In the normal state, we observe an abrupt drop in $\kappa_0/T$ upon crossing below $p^{\star}$, consistent with a drop in carrier density $n$ from $1 + p$ to $p$, the signature of the Pseudogap phase inferred from the Hall coefficient. A similar drop in $\kappa_0/T$ is observed at $H=0$, showing that the Pseudogap critical point and its signatures are unaffected by the magnetic field. In the normal state, the Wiedemann-Franz law, $\kappa_0/T=L_0/\rho(0)$, is obeyed at all dopings, including at the critical point where the electrical resistivity $\rho(T)$ is $T$-linear down to $T \to 0$. We conclude that the non-superconducting ground state of the Pseudogap phase at $T=0$ is a metal whose fermionic excitations carry heat and charge as conventional electrons do.
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Pseudogap temperature T* of cuprate superconductors from the Nernst effect
Physical Review B, 2018Co-Authors: O. Cyr-choiniere, R. Daou, F. Laliberte, C. Collignon, S. Badoux, D. Leboeuf, D. A. Bonn, Johan Juul Chang, Brad Ramshaw, W. N. HardyAbstract:We use the Nernst effect to delineate the boundary of the Pseudogap phase in the temperature-doping phase diagram of hole-doped cuprate superconductors. New data for the Nernst coefficient ν(T) of YBa2Cu3Oy (YBCO), La1.8−xEu0.2SrxCuO4 (Eu-LSCO), and La1.6−xNd0.4SrxCuO4 (Nd-LSCO) are presented and compared with previously published data on YBCO, Eu-LSCO, Nd-LSCO, and La2−xSrxCuO4 (LSCO). The temperature Tν at which ν/T deviates from its high-temperature linear behavior is found to coincide with the temperature at which the resistivity ρ(T) deviates from its linear-T dependence, which we take as the definition of the Pseudogap temperature T★—in agreement with the temperature at which the antinodal spectral gap detected in angle-resolved photoemission spectroscopy (ARPES) opens. We track T★ as a function of doping and find that it decreases linearly vs p in all four materials, having the same value in the three LSCO-based cuprates, irrespective of their different crystal structures. At low p,T★ is higher than the onset temperature of the various orders observed in underdoped cuprates, suggesting that these orders are secondary instabilities of the Pseudogap phase. A linear extrapolation of T★(p) to p=0 yields T★(p→0)≃TN(0), the Neel temperature for the onset of antiferromagnetic order at p=0, suggesting that there is a link between Pseudogap and antiferromagnetism. With increasing p,T★(p) extrapolates linearly to zero at p≃pc2, the critical doping below which superconductivity emerges at high doping, suggesting that the conditions which favor Pseudogap formation also favor pairing. We also use the Nernst effect to investigate how far superconducting fluctuations extend above the critical temperature Tc, as a function of doping, and find that a narrow fluctuation regime tracks Tc, and not T★. This confirms that the Pseudogap phase is not a form of precursor superconductivity, and fluctuations in the phase of the superconducting order parameter are not what causes Tc to fall on the underdoped side of the Tc dome.
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Pseudogap phase of cuprate superconductors confined by fermi surface topology
arXiv: Superconductivity, 2017Co-Authors: N Doironleyraud, Adrien Gourgout, Amirreza Ataei, F. Laliberte, S. Badoux, Clement Collignon, O Cyrchoiniere, Sophie Dufourbeausejour, Fazel Tafti, Marieeve BoulangerAbstract:The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the Pseudogap phase, which sets in at a doping $p^*$ that is material-dependent. What determines $p^*$ is currently an open question. Here we show that the Pseudogap cannot open on an electron-like Fermi surface, and can only exist below the doping $p_{FS}$ at which the large Fermi surface goes from hole-like to electron-like, so that $p^*$ $\leq$ $p_{FS}$. We derive this result from high-magnetic-field transport measurements in La$_{1.6-x}$Nd$_{0.4}$Sr$_x$CuO$_4$ under pressure, which reveal a large and unexpected shift of $p^*$ with pressure, driven by a corresponding shift in $p_{FS}$. This necessary condition for Pseudogap formation, imposed by details of the Fermi surface, is a strong constraint for theories of the Pseudogap phase. Our finding that $p^*$ can be tuned with a modest pressure opens a new route for experimental studies of the Pseudogap.
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Pseudogap phase of cuprate superconductors confined by fermi surface topology
Nature Communications, 2017Co-Authors: N Doironleyraud, Adrien Gourgout, Amirreza Ataei, F. Laliberte, S. Badoux, Clement Collignon, O Cyrchoiniere, Sophie Dufourbeausejour, Fazel Tafti, Marieeve BoulangerAbstract:The properties of cuprate high-temperature superconductors are largely shaped by competing phases whose nature is often a mystery. Chiefly among them is the Pseudogap phase, which sets in at a doping p* that is material-dependent. What determines p* is currently an open question. Here we show that the Pseudogap cannot open on an electron-like Fermi surface, and can only exist below the doping p FS at which the large Fermi surface goes from hole-like to electron-like, so that p* ≤ p FS. We derive this result from high-magnetic-field transport measurements in La1.6−x Nd0.4Sr x CuO4 under pressure, which reveal a large and unexpected shift of p* with pressure, driven by a corresponding shift in p FS. This necessary condition for Pseudogap formation, imposed by details of the Fermi surface, is a strong constraint for theories of the Pseudogap phase. Our finding that p* can be tuned with a modest pressure opens a new route for experimental studies of the Pseudogap. High-temperature superconductors exhibit Pseudogap behaviour that remains of unknown origin, despite many years of intensive study. Here the authors study the onset of the Pseudogap under pressure, providing evidence that it requires a hole-like Fermi surface and constraining future theoretical developments.
S Uchida - One of the best experts on this subject based on the ideXlab platform.
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Scattering interference signature of a pair density wave state in the cuprate Pseudogap phase
'Springer Science and Business Media LLC', 2021Co-Authors: Shuqiu Wang, S Uchida, H Eisaki, Peayush Choubey, Yi Xue Chong, Weijiong Chen, Wangping Ren, Peter J. Hirschfeld, J. Séamus C. DavisAbstract:The Pseudogap phase in cuprate superconductors is predicted to be a pair density wave state (PDW) but experimental evidence has been lacking. Here, the authors detect the temperature evolution of energy gap modulations and scattering interference signature suggesting the Bi2Sr2CaDyCu2O8 Pseudogap phase contains a PDW
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phase competition in trisected superconducting dome
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: I M Vishik, D H Lu, M Hashimoto, Ruihua He, F Schmitt, R G Moore, Chao Zhang, W Meevasana, T Sasagawa, S UchidaAbstract:A detailed phenomenology of low energy excitations is a crucial starting point for microscopic understanding of complex materials, such as the cuprate high-temperature superconductors. Because of its unique momentum-space discrimination, angle-resolved photoemission spectroscopy (ARPES) is ideally suited for this task in the cuprates, where emergent phases, particularly superconductivity and the Pseudogap, have anisotropic gap structure in momentum space. We present a comprehensive doping- and temperature-dependence ARPES study of spectral gaps in Bi2Sr2CaCu2O8+δ, covering much of the superconducting portion of the phase diagram. In the ground state, abrupt changes in near-nodal gap phenomenology give spectroscopic evidence for two potential quantum critical points, p = 0.19 for the Pseudogap phase and p = 0.076 for another competing phase. Temperature dependence reveals that the Pseudogap is not static below Tc and exists p > 0.19 at higher temperatures. Our data imply a revised phase diagram that reconciles conflicting reports about the endpoint of the Pseudogap in the literature, incorporates phase competition between the superconducting gap and Pseudogap, and highlights distinct physics at the edge of the superconducting dome.
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intra unit cell electronic nematicity of the high tc copper oxide Pseudogap states
Nature, 2010Co-Authors: H Eisaki, Michael J Lawler, K Fujita, A Schmidt, Y Kohsaka, S UchidaAbstract:Within the Pseudogap phase of the high-Tc superconductors, it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Lawler et al. report the determination of a quantitative order parameter representing intra-unit cell nematicity — the breaking of rotational symmetry by the electronic structure within each CuO2 unit cell. They find electronic differences at the two oxygen sites within each unit cell. If the excitations seen by different techniques in the Pseudogap phase all have the same origin, they would represent weakly magnetic states at the O sites, the electronic structure of which breaks a 90° rotational symmetry. In the high-transition-temperature superconductors, the Pseudogap phase becomes predominant when the density of doped holes is reduced. In this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here, images of the intra-unit-cell states in underdoped Bi2Sr2CaCu2O8 + δ are studied, revealing electronic nematicity of the states close to the Pseudogap energy. In the high-transition-temperature (high-Tc) superconductors the Pseudogap phase becomes predominant when the density of doped holes is reduced1. Within this phase it has been unclear which electronic symmetries (if any) are broken, what the identity of any associated order parameter might be, and which microscopic electronic degrees of freedom are active. Here we report the determination of a quantitative order parameter representing intra-unit-cell nematicity: the breaking of rotational symmetry by the electronic structure within each CuO2 unit cell. We analyse spectroscopic-imaging scanning tunnelling microscope images of the intra-unit-cell states in underdoped Bi2Sr2CaCu2O8 + δ and, using two independent evaluation techniques, find evidence for electronic nematicity of the states close to the Pseudogap energy. Moreover, we demonstrate directly that these phenomena arise from electronic differences at the two oxygen sites within each unit cell. If the characteristics of the Pseudogap seen here and by other techniques all have the same microscopic origin, this phase involves weak magnetic states at the O sites that break 90°-rotational symmetry within every CuO2 unit cell.
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low energy electronic structure of the high tc cuprates la2 xsrxcuo4 studied by angle resolved photoemission spectroscopy
Journal of Physics: Condensed Matter, 2007Co-Authors: T Yoshida, T Kakeshita, S Uchida, H Eisaki, X Zhou, D H Lu, Yoichi Ando, Z Hussain, Seiki Komiya, Z X ShenAbstract:We have performed a systematic angle-resolved photoemission spectroscopy (ARPES) study of the high-Tc cuprates La2−xSrxCuO4, ranging from the underdoped insulator to the superconductor to the overdoped metal. We have revealed a systematic doping evolution of the band dispersions and (underlying) Fermi surfaces, Pseudogap and quasi-particle features under the influence of strong electron–electron interaction and electron–phonon interaction. The unusual transport and thermodynamic properties are explained by taking into account the Pseudogap opening and the Fermi arc formation, due to which the carrier number decreases as the doped hole concentration decreases.
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vortex like excitations and the onset of superconducting phase fluctuation in underdoped la 2 x sr x cuo 4
Nature, 2000Co-Authors: N P Ong, Yuchiun Wang, T Kakeshita, S UchidaAbstract:Two general features of a superconductor, which appear at the critical temperature, are the formation of an energy gap and the expulsion of magnetic flux (the Meissner effect). In underdoped copper oxides, there is strong evidence that an energy gap (the Pseudogap1) opens up at a temperature significantly higher than the critical temperature (by 100–220 K). Certain features of the Pseudogap suggest that it is closely related to the gap that appears at the critical temperature (for example, the variation of the gap magnitudes around the Fermi surface and their maximum amplitudes are very similar2,3). However, the Meissner effect is absent in the Pseudogap state. The nature of the Pseudogap state, and its relation (if any) to the superconducting state are central issues in understanding copper oxide superconductivity. Recent evidence suggests that, in the underdoped regime, the Meissner state is destroyed above the critical temperature by strong phase fluctuations1,4,5,6,7 (as opposed to a vanishing of the superfluid density). Here we report evidence for vortices (or vortex-like excitations) in La2-xSrxCuO4 at temperatures significantly above the critical temperature. A thermal gradient is applied to the sample in a magnetic field. Vortices are detected by the large transverse electric field produced as they diffuse down the gradient (the Nernst effect). We find that the Nernst signal is anomalously enhanced at temperatures as high as 150 K.
Guoqing Zheng - One of the best experts on this subject based on the ideXlab platform.
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carrier concentration dependence of the Pseudogap ground state of superconducting bi sr x la x cuo δ revealed by cu nuclear magnetic resonance in very high magnetic fields
Physical Review Letters, 2010Co-Authors: Shinji Kawasaki, C T Lin, Philip Kuhns, A P Reyes, Guoqing ZhengAbstract:We report the results of the Knight shift by Cu-63,Cu-65-NMR measurements on single-layered copper-oxide Bi2Sr2-xLaxCuO6+delta conducted under very high magnetic fields up to 44 T. The magnetic field suppresses superconductivity completely, and the Pseudogap ground state is revealed. The Cu-63-NMR Knight shift shows that there remains a finite density of states at the Fermi level in the zero-temperature limit, which indicates that the Pseudogap ground state is a metallic state with a finite volume of Fermi surface. The residual density of states in the Pseudogap ground state decreases with decreasing doping (increasing x) but remains quite large even at the vicinity of the magnetically ordered phase of x >= 0.8, which suggests that the density of states plunges to zero upon approaching the Mott insulating phase.
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carrier concentration dependence of the Pseudogap ground state of superconductingbi2sr2 xlaxcuo6 δrevealed bycu63 65 nuclear magnetic resonance in very high magnetic fields
Physical Review Letters, 2010Co-Authors: Shinji Kawasaki, C T Lin, Philip Kuhns, A P Reyes, Guoqing ZhengAbstract:We report the results of the Knight shift by $^{63,65}\mathrm{Cu}$-NMR measurements on single-layered copper-oxide ${\mathrm{Bi}}_{2}{\mathrm{Sr}}_{2\ensuremath{-}x}{\mathrm{La}}_{x}{\mathrm{CuO}}_{6+\ensuremath{\delta}}$ conducted under very high magnetic fields up to 44 T. The magnetic field suppresses superconductivity completely, and the Pseudogap ground state is revealed. The $^{63}\mathrm{Cu}$-NMR Knight shift shows that there remains a finite density of states at the Fermi level in the zero-temperature limit, which indicates that the Pseudogap ground state is a metallic state with a finite volume of Fermi surface. The residual density of states in the Pseudogap ground state decreases with decreasing doping (increasing $x$) but remains quite large even at the vicinity of the magnetically ordered phase of $x\ensuremath{\ge}0.8$, which suggests that the density of states plunges to zero upon approaching the Mott insulating phase.
