223 citations · 813 across the 24 of their papers we have counts for
24 papers
Crystal structures and high-temperature superconductivity in molybdenum-hydrogen binary system under high pressure
Aiqin Yang, Xiangru Tao, Yundi Quan +1
Motivated by advances in hydrogen-rich superconductors in the past decades, we conducted variable-composition structural searches in Mo-H binary system at high pressure. A new comp…
A first-principles investigation of the origin of superconductivity in TlBi
Aiqin Yang, Xiangru Tao, Yundi Quan +1
The intermetallic compound TlBi crystallizes in the MgB structure and becomes superconducting below 6.2 K. Considering that both Tl and Bi have heavy atomic masses, it is p…
Leading components and pressure-induced color changes in N-doped lutetium hydride
Xiangru Tao, Aiqin Yang, Shuxiang Yang +2
Recent experimental study by Dias {\it et al.} claims to have discovered room-temperature superconductivity in lutetium-nitrogen-hydrogen system at 1 GPa [Nature 615, 244 (2023)],…
Magnetic molecule tunnel heterojunctions
Xuanyuan Jiang, Andrew Brooks, Shuanglong Liu +6
We characterize molecular magnet heterojunctions in which sublimated CoPc films as thin as 5 nm are sandwiched between transparent conducting bottom-layer indium tin oxide and top-…
Spin triplet superconductivity driven by finite momentum spin fluctuations
Andreas Kreisel, Yundi Quan, P. J. Hirschfeld
A small number of superconductors are believed to exhibit intrinsic spin triplet pairing, and they are often discussed in terms of a simple, He-like picture where ferromagnetic…
Dirac lines and loop at the Fermi level in the Time-Reversal Symmetry Breaking Superconductor LaNiGa
Jackson R. Badger, Yundi Quan, Matthew C. Staab +12
Unconventional superconductors have Cooper pairs with lower symmetries than in conventional superconductors. In most unconventional superconductors, the additional symmetry breakin…
MoB2 under Pressure: Superconducting Mo Enhanced by Boron
Yundi Quan, Kwan-woo Lee, Warren E. Pickett
The discovery of the first high critical temperature (Tc) transition metal diboride superconductor, MgB2 structure alpha-MoB2 under pressure with Tc up to 32 K at 100 GPa, provides…
Creating superconductivity in WB2 through pressure-induced metastable planar defects
J. Lim, A. C. Hire, Y. Quan +11
High-pressure electrical resistivity measurements reveal that the mechanical deformation of ultra-hard WB2 during compression induces superconductivity above 50 GPa with a maximum…
Machine learning of superconducting critical temperature from Eliashberg theory
S. R. Xie, Y. Quan, A. C. Hire +11
The Eliashberg theory of superconductivity accounts for the fundamental physics of conventional electron-phonon superconductors, including the retardation of the interaction and th…
Towards high-throughput superconductor discovery via machine learning
Stephen R. Xie, Y. Quan, Ajinkya Hire +5
Even though superconductivity has been studied intensively for more than a century, the vast majority of superconductivity research today is carried out in nearly the same manner a…
Superconductivity of -Gallium
Yundi Quan, Peter J. Hirschfeld, Richard G. Hennig
Elemental gallium can exist in several phases under ambient conditions. The stable phase has a superconducting transition temperature, , of 0.9~K. By contrast, the o…
High pressure study of low-Z superconductor BeRe
J. Lim, A. C. Hire, Y. Quan +11
With , BeRe exhibits one of the highest critical temperatures among Be-rich compounds. We have carried out a series of high-pressure electrical resi…
A15 NbSi -- A "high" Tc superconductor synthesized at a pressure of one megabar and metastable at ambient conditions
Jinhyuk Lim, J. S. Kim, Ajinkya C. Hire +6
A15 NbSi is, until now, the only high temperature superconductor produced at high pressure (~110 GPa) that has been successfully brought back to room pressure conditions in a m…
Remarkable low-energy properties of the pseudogapped semimetal BePt
L. Fanfarillo, J. J. Hamlin, R. G. Hennig +7
We report measurements and calculations on the properties of the intermetallic compound BePt. High-quality polycrystalline samples show a nearly constant temperature dependence…
Strong Particle-Hole Symmetry Breaking in a 200 kelvin Superconductor
Soham S. Ghosh, Yundi Quan, Warren E. Pickett
The superconducting state of metals has long provided a classic example of particle-hole symmetry (PHS) at low energy. Fermionic self-energy results based on first principles theor…
How Compressed Hydrides Produce Room Temperature Superconductivity
Yundi Quan, Soham S. Ghosh, Warren E. Pickett
The 2014-2015 prediction, discovery, and confirmation of record high temperature superconductivity above 200K in HS, followed by the 2018 extension to superconductivity in the…
Collapse of critical nematic fluctuations in FeSe under pressure
Pierre Massat, Yundi Quan, Romain Grasset +8
We report the evolution of the electronic nematic susceptibility in FeSe via Raman scattering as a function of hydrostatic pressure up to 5.8 GPa where the superconducting transiti…
A single nodal loop of accidental degeneracies in minimal symmetry: triclinic CaAs
Y. Quan, Z. P. Yin, W. E. Pickett
The existence of closed loops of degeneracies in crystals has been intimately connected to associated crystal symmetries, raising the question: what is the minimum symmetry require…
van Hove singularities and spectral smearing in high temperature superconducting H3S
Yundi Quan, Warren E. Pickett
The superconducting phase of hydrogen sulfide at Tc=200 K observed by Drozdov and collaborators at pressures around 200 GPa is simple bcc Im-3m H3S, predicted beforehand by Duan {\…
Disturbing the dimers: electron- and hole-doping in the intermetallic insulator FeGa
Antia S. Botana, Yundi Quan, Warren E. Pickett
Insulating FeGa poses peculiar puzzles beyond the occurrence of an electronic gap in an intermetallic compound. This Fe-based material has a very distinctive structural charact…
Analysis of charge states in the mixed valent ionic insulator AgO
Yundi Quan, Warren E. Pickett
The doubly ionized copper ion provides, originally in LaCuO and later in many more compounds, the platform for high temperature superconductivity when it is forced to…
Charge States of Ions, and Mechanisms of Charge-Ordering Transitions
W. E. Pickett, Y. Quan, V. Pardo
To gain insight into the mechanism of charge-ordering transitions, which conventionally are pictured as a disproportionation of an ion M as 2M M + M…
Electronic fine structure in the nickel carbide superconductor ThNiC
Y. Quan, W. E. Pickett
The recently reported nickel carbide superconductor, body centered tetragonal ThNiC with T = 8.5 K increasing to 11.2 K upon alloying Th with Sc, is found to h…
Formal Valence, Occupation, and Charge-Order Transitions
Yundi Quan, Victor Pardo, Warren E. Pickett
While the formal valence and charge state concepts have been tremendously important in materials physics and chemistry, their very loose connection to actual charge leads to uncert…