Publications

@article{Lawson2018,

title = {Measurements of the NMR Knight shift tensor and nonlinear magnetization in URu$_2$Si$_2$},

author = {M. Lawson and B. T. Bush and T. Kissikov and Z. Brubaker and K. R. Shirer and J. R. Jeffries and S. Ran and I. Jeon and M. B. Maple and N. J. Curro},

doi = {10.1103/physrevb.97.075138},

year  = {2018},

date = {2018-02-01},

urldate = {2018-02-01},

journal = {Phys. Rev. B},

volume = {97},

number = {7},

pages = {075138},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{EFGnematicity,

title = {Local nematic susceptibility in stressed BaFe$_2$As$_2$ from NMR electric field gradient measurements},

author = {T. Kissikov and R. Sarkar and M. Lawson and B. T. Bush and E. I. Timmons and M. A. Tanatar and R. Prozorov and S. L. Bud'ko and P. C. Canfield and R. M. Fernandes and W. F. Goh and W. E. Pickett and N. J. Curro},

doi = {10.1103/physrevb.96.241108},

year  = {2017},

date = {2017-12-01},

journal = {Phys. Rev. B},

volume = {96},

number = {24},

pages = {241108(R)},

publisher = {American Physical Society (APS)},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{FORCinFeTe,

title = {First-order reversal curve of the magnetostructural phase transition in FeTe},

author = {M. K. Frampton and J. Crocker and D. A. Gilbert and N. Curro and Kai Liu and J. A. Schneeloch and G. D. Gu and R. J. Zieve},

doi = {10.1103/PhysRevB.95.214402},

year  = {2017},

date = {2017-06-01},

journal = {Phys. Rev. B},

volume = {95},

pages = {214402},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{MendesQCPimpurities,

title = {Impurities near an antiferromagnetic-singlet quantum critical point},

author = {T. Mendes-Santos and N. C. Costa and G. Batrouni and N. Curro and R. R. Santos and T. Paiva and R. T. Scalettar},

url = {http://link.aps.org/doi/10.1103/PhysRevB.95.054419},

doi = {10.1103/PhysRevB.95.054419},

year  = {2017},

date = {2017-02-01},

journal = {Phys. Rev. B},

volume = {95},

pages = {054419},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{NVinDAC,

title = {Optically detected magnetic resonance of nitrogen vacancies in a diamond anvil cell using designer diamond anvils},

author = {L. G. Steele and M. Lawson and M. Onyszczak and B. T. Bush and Z. Mei and A. P. Dioguardi and J. King and A. Parker and A. Pines and S. T. Weir and W. Evans and K. Visbeck and Y. K. Vohra and N. J. Curro},

url = {https://doi.org/10.1063/1.5004153},

doi = {10.1063/1.5004153},

year  = {2017},

date = {2017-01-01},

urldate = {2017-01-01},

journal = {Appl. Phys. Lett.},

volume = {111},

number = {22},

pages = {221903},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{KissikovStrainProbe,

title = {Nuclear magnetic resonance probe head design for precision strain control},

author = {T. Kissikov and R. Sarkar and B. T. Bush and M. Lawson and P. C. Canfield and N. J. Curro},

url = {http://dx.doi.org/10.1063/1.5002631},

doi = {10.1063/1.5002631},

year  = {2017},

date = {2017-01-01},

journal = {Rev. Sci. Instrum.},

volume = {88},

number = {10},

pages = {103902},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ShirerPdopedURS2017,

title = {NMR investigation of antiferromagnetism and coherence in URu$_2$Si$_2-x$P$_x$},

author = {K. R. Shirer and M. Lawson and T. Kissikov and B. T. Bush and A. Gallagher and K. -W. Chen and R. E. Baumbach and N. J. Curro},

url = {http://link.aps.org/doi/10.1103/PhysRevB.95.041107},

doi = {10.1103/PhysRevB.95.041107},

year  = {2017},

date = {2017-01-01},

journal = {Phys. Rev. B},

volume = {95},

pages = {041107},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{NMRnematicStrainBa122PRB2016,

title = {NMR study of nematic spin fluctuations in a detwinned single crystal of underdoped Ba(Fe$_1-x$Co$_x$)$_2$As$_2$},

author = {T. Kissikov and A. P. Dioguardi and E. I. Timmons and M. A. Tanatar and R. Prozorov and S. L. Bud'ko and P. C. Canfield and R. M. Fernandes and N. J. Curro},

url = {http://link.aps.org/doi/10.1103/PhysRevB.94.165123},

doi = {10.1103/PhysRevB.94.165123},

year  = {2016},

date = {2016-10-01},

journal = {Phys. Rev. B},

volume = {94},

pages = {165123},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{BenAliPAMdopants2016,

title = {Impurity-induced antiferromagnetic domains in the periodic Anderson model},

author = {A. Benali and Z. J. Bai and N. J. Curro and R. T. Scalettar},

url = {http://link.aps.org/doi/10.1103/PhysRevB.94.085132},

doi = {10.1103/PhysRevB.94.085132},

year  = {2016},

date = {2016-08-01},

journal = {Phys. Rev. B},

volume = {94},

pages = {085132},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{DioguardiPdoped2015,

title = {NMR Evidence for Inhomogeneous Nematic Fluctuations in BaFe$_2$As$_2-x$P$_x$},

author = {A. P. Dioguardi and T. Kissikov and C. H. Lin and K. R. Shirer and M. M. Lawson and H. -J. Grafe and J. -H. Chu and I. R. Fisher and R. M. Fernandes and N. J. Curro},

url = {http://link.aps.org/doi/10.1103/PhysRevLett.116.107202},

doi = {10.1103/PhysRevLett.116.107202},

year  = {2016},

date = {2016-03-01},

journal = {Phys. Rev. Lett.},

volume = {116},

pages = {107202},

publisher = {American Physical Society},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{NissonCEFSOC2016,

title = {Nuclear magnetic resonance Knight shifts in the presence of strong spin-orbit and crystal-field potentials},

author = {D M Nisson and N J Curro},

url = {http://stacks.iop.org/1367-2630/18/i=7/a=073041},

doi = {10.1088/1367-2630/18/7/073041},

year  = {2016},

date = {2016-01-01},

journal = {New J. Phys.},

volume = {18},

number = {7},

pages = {073041},

abstract = {In recent years there has been increasing interest in materials with strong spin–orbit coupling (SOC). Nuclear magnetic resonance is a valuable microscopic probe of such systems because of the hyperfine interactions between the nuclear spins and the electron degrees of freedom. In materials with weak SOC the NMR Knight shift contains two contributions: one from the electron orbital susceptibility and the other from the electron spin susceptibility. These contributions can be separated by plotting the Knight shift versus the bulk susceptibility and extracting the slope and intercept. Here we examine the case where the SOC is non-negligible, in which case the slope and intercept are no longer simply related to these two contributions. These results have important implications for NMR studies of heavy fermions, as well as 4d and 5d systems.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ShirerURSpressure,

title = {$^29$Si nuclear magnetic resonance study of URu$_2$Si$_2$ under pressure},

author = {K. R. Shirer and A. P. Dioguardi and B. T. Bush and J. Crocker and C. H. Lin and P. Klavins and J. C. Cooley and M. B. Maple and K. B. Chang and K. R. Poeppelmeier and N. J. Curro},

url = {http://www.sciencedirect.com/science/article/pii/S0921452615303227},

doi = {10.1016/j.physb.2015.11.018},

issn = {0921-4526},

year  = {2016},

date = {2016-01-01},

journal = {Phys. B},

volume = {481},

pages = {232--235},

abstract = {We report 29Si nuclear magnetic resonance measurements of single crystals and aligned powders of URu2Si2 under pressure in the hidden order and paramagnetic phases. We find that the Knight shift decreases with applied pressure, consistent with previous measurements of the static magnetic susceptibility. Previous measurements of the spin lattice relaxation time revealed a partial suppression of the density of states below 30 K. This suppression persists under pressure, and the onset temperature is mildly enhanced.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{ROPP2016,

title = {Nuclear magnetic resonance in Kondo lattice systems},

author = {Nicholas J Curro},

url = {http://stacks.iop.org/0034-4885/79/i=6/a=064501},

doi = {10.1088/0034-4885/79/6/064501},

year  = {2016},

date = {2016-01-01},

journal = {Rep. Prog. Phys.},

volume = {79},

number = {6},

pages = {064501},

abstract = {Nuclear magnetic resonance has emerged as a vital tool to explore the fundamental physics of Kondo lattice systems. Because nuclear spins experience two different hyperfine couplings to the itinerant conduction electrons and to the local f moments, the Knight shift can probe multiple types of spin correlations that are not accessible via other techniques. The Knight shift provides direct information about the onset of heavy electron coherence and the emergence of the heavy electron fluid.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Yang2015,

title = {Quantum critical scaling and superconductivity in heavy electron materials},

author = {Yi-feng Yang and David Pines and N. J. Curro},

url = {http://dx.doi.org/10.1103/PhysRevB.92.195131},

doi = {10.1103/physrevb.92.195131},

issn = {1550-235X},

year  = {2015},

date = {2015-11-01},

journal = {Phys. Rev. B},

volume = {92},

number = {19},

pages = {195131},

publisher = {American Physical Society (APS)},

abstract = {We use the two fluid model to determine the conditions under which the nuclear spin-lattice lattice relaxation rate T1 of candidate heavy quantum critical superconductors can exhibit scaling behavior and find that it can occur if and only if their “hidden” quantum critical spin fluctuations give rise to a temperature-independent intrinsic heavy electron spin-lattice relaxation rate. The resulting scaling of T1 with the strength of the heavy electron component and the coherence temperature T* provides a simple test for their presence at pressures at which the superconducting transition temperature Tc is maximum and is proportional to T*. These findings support the previously noted partial scaling of the spin-lattice relaxation rate with Tc in a number of important heavy electron materials and provide additional evidence that in these materials their optimal superconductivity originates in the quantum critical spin fluctuations associated with a nearby phase transition from partially localized to fully itinerant quasiparticles.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lin2015,

title = {Evolution of hyperfine parameters across a quantum critical point in CeRhIn$_5$},

author = {C. H. Lin and K. R. Shirer and J. Crocker and A. P. Dioguardi and M. M. Lawson and B. T. Bush and P. Klavins and N. J. Curro},

url = {http://dx.doi.org/10.1103/PhysRevB.92.155147},

doi = {10.1103/physrevb.92.155147},

issn = {1550-235X},

year  = {2015},

date = {2015-10-01},

journal = {Phys. Rev. B},

volume = {92},

number = {15},

pages = {155147},

publisher = {American Physical Society (APS)},

abstract = {We report nuclear magnetic resonance (NMR) data for both the In(1) and In(2) sites in the heavy-fermion material CeRhIn5 under hydrostatic pressure. The Knight shift data reveal a suppression of the hyperfine coupling to the In(1) site as a function of pressure, and the electric field gradient nu_alphaalpha at the In(2) site exhibits a change of slope dnu/dP at Pc1=1.75 GPa. These changes to the coupling constants reflect alterations to the electronic structure at the quantum critical point.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Dioguardi2015,

title = {NMR evidence for inhomogeneous glassy behavior driven by nematic fluctuations in iron arsenide superconductors},

author = {A. P. Dioguardi and M. M. Lawson and B. T. Bush and J. Crocker and K. R. Shirer and D. M. Nisson and T. Kissikov and S. Ran and S. L. Budko and P. C. and Canfield},

url = {http://dx.doi.org/10.1103/PhysRevB.92.165116},

doi = {10.1103/physrevb.92.165116},

issn = {1550-235X},

year  = {2015},

date = {2015-10-01},

journal = {Phys. Rev. B},

volume = {92},

number = {16},

pages = {165116},

publisher = {American Physical Society (APS)},

abstract = {We present As75 nuclear magnetic resonance spin-lattice and spin-spin relaxation rate data in Ba(Fe1-xCox)2As2 and Ba(Fe1-xCux)2As2 as a function of temperature, doping, and magnetic field. The relaxation curves exhibit a broad distribution of relaxation rates, consistent with inhomogeneous glassy behavior up to 100 K. The doping and temperature response of the width of the dynamical heterogeneity is similar to that of the nematic susceptibility measured by elastoresistance measurements. We argue that quenched random fields which couple to the nematic order give rise to a nematic glass that is reflected in the spin dynamics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Shockley2015,

title = {NMR evidence of anisotropic Kondo liquid behavior in CeIrIn$_5$},

author = {A. C. Shockley and K. R. Shirer and J. Crocker and A. P. Dioguardi and C. H. Lin and D. M. Nisson and N. apRoberts-Warren and P. Klavins and N. J. Curro},

url = {http://dx.doi.org/10.1103/PhysRevB.92.085108},

doi = {10.1103/physrevb.92.085108},

issn = {1550-235X},

year  = {2015},

date = {2015-08-01},

journal = {Phys. Rev. B},

volume = {92},

number = {8},

pages = {085108},

publisher = {American Physical Society (APS)},

abstract = {We report detailed Knight-shift measurements of the two indium sites in the heavy-fermion compound CeIrIn5 as a function of temperature and field orientation. We find that the Knight-shift anomaly is orientation dependent, with a crossover temperature T* that varies by 50% as the field is rotated from (001) to (100). This result suggests that the hybridization between the Ce 4f states and the itinerant conduction electrons is anisotropic, a result that reflects its collective origin, and may lead to anisotropic Kondo liquid behavior and unconventional superconductivity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Jiang2014,

title = {Universal Knight shift anomaly in the periodic Anderson model},

author = {M. Jiang and N. J. Curro and R. T. Scalettar},

url = {http://dx.doi.org/10.1103/PhysRevB.90.241109},

doi = {10.1103/physrevb.90.241109},

issn = {1550-235X},

year  = {2014},

date = {2014-12-01},

journal = {Phys. Rev. B},

volume = {90},

number = {24},

pages = {241109},

publisher = {American Physical Society (APS)},

abstract = {We report a determinant Quantum Monte Carlo investigation which quantifies the behavior of the susceptibility and the entropy in the framework of the periodic Anderson model, focusing on the evolution with different degree of conduction electron (c)-local moment (f) hybridization. These results capture the behavior observed in several experiments, including the universal behavior of the NMR Knight shift anomaly below the crossover temperature T*. We find that T* is a measure of the onset of c-f correlations and grows with increasing hybridization. These results suggest that the NMR Knight shift and spin-lattice relaxation rate measurements in non-Fermi-liquid materials are strongly influenced by the temperature dependence of the c-f kinetic energy. Our results provide a microscopic basis for the phenomenological two-fluid model of Kondo lattice behavior, and its evolution with pressure and temperature.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Seo2014,

title = {Disorder in quantum critical superconductors},

author = {S. Seo and Xin Lu and J-X. Zhu and R. R. Urbano and N. Curro and E. D. Bauer and V. A. Sidorov and L. D. Pham and Tuson Park and Z. Fisk and J. D. Thompson},

url = {http://dx.doi.org/10.1038/nphys2820},

doi = {10.1038/nphys2820},

issn = {1745-2481},

year  = {2014},

date = {2014-12-01},

urldate = {2014-12-01},

journal = {Nat. Phys.},

volume = {10},

pages = {120--125},

publisher = {Nature Publishing Group},

abstract = {In four classes of materials—the layered copper oxides, organics, iron pnictides and heavy-fermion compounds—an unconventional superconducting state emerges as a magnetic transition is tuned towards absolute zero temperature, that is, towards a magnetic quantum critical point1 (QCP). In most materials, the QCP is accessed by chemical substitution or applied pressure. CeCoIn5 is one of the few materials that are ‘born’ as a quantum critical superconductor2, 3, 4 and, therefore, offers the opportunity to explore the consequences of chemical disorder. Cadmium-doped crystals of CeCoIn5 are a particularly interesting case where Cd substitution induces long-range magnetic order5, as in Zn-doped copper oxides6, 7. Applied pressure globally suppresses the Cd-induced magnetic order and restores bulk superconductivity. Here we show, however, that local magnetic correlations, whose spatial extent decreases with applied pressure, persist at the extrapolated QCP. The residual droplets of impurity-induced magnetic moments prevent the reappearance of conventional signatures of quantum criticality, but induce a heterogeneous electronic state. These discoveries show that spin droplets can be a source of electronic heterogeneity and emphasize the need for caution when interpreting the effects of tuning a correlated system by chemical substitution.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{NissonBi2Se3nano2014,

title = {Anomalous nuclear magnetic resonance spectra in Bi$_2$Se$_3$ nanowires},

author = {D. M. Nisson and A. P. Dioguardi and X. Peng and D. Yu and N. J. Curro},

url = {http://link.aps.org/doi/10.1103/PhysRevB.90.125121},

doi = {10.1103/PhysRevB.90.125121},

year  = {2014},

date = {2014-09-01},

journal = {Phys. Rev. B},

volume = {90},

pages = {125121},

publisher = {American Physical Society},

abstract = {We report Bi209 nuclear magnetic resonance spectra in nanowires and single crystals of Bi2Se3. Crystals were powdered to simulate the random orientation of the nanowires, and the spectra are compared with theoretical expectations derived via an orientational study of a single crystal. The nanowire spectra are consistent with the randomly oriented powders; however, we find an unusual suppression of signal intensity as a function of field orientation that may be associated with screening by surface currents.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}