Gang Cao

American physicist

Gang Cao is an American condensed matter physicist, academic, author, and researcher. He is a professor of physics at the University of Colorado Boulder.^[1] and Director of Center for Experiments on Quantum Materials.

Cao has published two books and more than 260 articles. His work has been cited more than 15,500 times, and his h-index is 65, according to Google Scholar.^[2] Cao's research interests focus on discovery and synthesis of 4d- and 5d-transition metal materials and study of physical properties of these materials as functions of temperature, magnetic field, pressure and electrical current. His most recent book entitled Physics of Spin-Orbit-Coupled Oxides reviews recent work in the field of 4d- and 5d-transition metal oxides, a field he helped initiate in the late 1990s.^[3]

Cao was an elected Fellow of the American Physical Society (DCMP) in 2009.^[4]

Education

Cao received his Ph.D. in Physics under direction of Jack E. Crow at Temple University in Philadelphia in 1993.^[1]

Career

Upon receiving his Ph.D. degree, Cao joined the National High Magnetic Field Laboratory (NHMFL) as a Postdoc (1993-1995), Assistant Scientist (1995-1998), and then Associate Scientist (1998-2002). He then relocated to the University of Kentucky as an Associate Professor of Physics in 2002. He was promoted to Professor in 2007 and became a Jack and Linda Gill Eminent Professor in 2011. He served as a founding Director of Center for Advanced Materials at Kentucky from 2008 to 2016. In 2015, he was awarded the Albert D. & Elizabeth H. Kirwan Memorial Prize for Outstanding Contributions to Original Research or Creative Scholarship.^[5] In 2016, he joined the faculty of University of Colorado at Boulder as a Professor of Physics.^[1] He is now Director of Center for Experiments on Quantum Materials at University of Colorado at Boulder.

Research

Cao's research primarily focuses on discovery and synthesis of 4d- and 5d-transition metal materials and study of physical properties of these materials in single-crystal form as functions of temperature, magnetic field, pressure and electrical current,^[6][7] often at extreme conditions of high magnetic fields, high pressures and ultralow temperatures. In the early 1990s, he became interested in new materials, particularly those containing no 3d-transition metals, and started exploring ruthenates,^[8][9][10] rhodates,^[11] and iridates^{[12][13][14][15]} in search of novel materials and phenomena. This research effort has been intensified and extended over the last two decades. Cao is among very few who conducted pioneering studies of 4d- and 5d-transition metal oxides whose physics is dictated by a delicate interplay between the Coulomb and spin-orbit interactions.

Bibliography

Books

• Frontiers of 4d- and 5d-transition Metal Oxides (2013), Gang Cao and Lance E. DeLong, ed. ISBN 9789814374866; World Scientific
• Physics of Spin-Orbit-Coupled Oxides (2021), Gang Cao and Lance E. DeLong, ISBN 9780199602025; Oxford University Press

Selected articles

• Cao, G., McCall, S., Crow, J. E., & Guertin, R. P. (1997). Observation of a metallic antiferromagnetic phase and metal to nonmetal transition in Ca 3 Ru 2 O 7. Physical Review Letters, 78(9), 1751.
• Cao, G., McCall, S., Shepard, M., Crow, J. E., & Guertin, R. P. (1997). Thermal, magnetic, and transport properties of single-crystal Sr 1− x Ca x RuO 3 (0<~ x<~ 1. 0). Physical Review B, 56(1), 321.
• Cao, G., McCall, S., Shepard, M., Crow, J. E., & Guertin, R. P. (1997). Magnetic and transport properties of single-crystal Ca 2 RuO 4: Relationship to superconducting Sr 2 RuO 4. Physical Review B, 56(6), R2916.
• Cao, G., Bolivar, J., McCall, S., Crow, J. E., & Guertin, R. P. (1998). Weak ferromagnetism, metal-to-nonmetal transition, and negative differential resistivity in single-crystal Sr 2 IrO 4. Physical Review B 57(18), R11039.
• Cao, G., Xin, Y., Alexander, C. S., Crow, J. E., Schlottmann, P., Crawford, M. K., ... & Marshall, W. (2002). Anomalous magnetic and transport behavior in the magnetic insulator Sr 3 Ir 2 O 7. Physical Review B, 66(21), 214412.
• Lin, X. N., Zhou, Z. X., Durairaj, V., Schlottmann, P., & Cao, G. (2005). Colossal Magnetoresistance by Avoiding a Ferromagnetic State in the Mott System Ca 3 Ru 2 O 7. Physical Review Letters, 95(1), 017203.
• Kim, B. J., Jin, H., Moon, S. J., Kim, J. Y., Park, B. G., Leem, C. S., ... & Rotenberg, E. (2008). Novel J eff= 1/2 Mott state induced by relativistic spin-orbit coupling in Sr2IrO4. Physical Review Letters, 101(7), 076402.
• Cao, G., Durairaj, V., Chikara, S., DeLong, L. E., & Schlottmann, P. (2008). Observation of strong spin valve effect in bulk Ca3(Ru1-xCrx)2O7. Physical review letters, 100(1), 016604. Observation of Strong Spin Valve Effect in Bulk ${\mathrm{Ca}}_{3}({\mathrm{Ru}}_{1\ensuremath{-}x}{\mathrm{Cr}}_{x}{)}_{2}{\mathrm{O}}_{7}$
• Qi, T. F., Korneta, O. B., Parkin, S., De Long, L. E., Schlottmann, P., & Cao, G. (2010). Negative volume thermal expansion via orbital and magnetic orders in Ca 2 Ru 1− x Cr x O 4 (0< x< 0.13). Physical Review Letters, 105(17), 177203.
• Ge, M., Qi, T. F., Korneta, O. B., De Long, D. E., Schlottmann, P., Crummett, W. P., & Cao, G. (2011). Lattice-driven magnetoresistivity and metal-insulator transition in single-layered iridates. Physical Review B, 84(10), 100402.
• Cao, G., Qi, T. F., Li, L., Terzic, J., Yuan, S. J., DeLong, L. E., ... & Kaul, R. K. (2014). Novel Magnetism of Ir 5+(5 d 4) Ions in the Double Perovskite Sr 2 YIrO 6. Physical Review Letters, 112(5), 056402.
• Cao, G., Terzic, J., Zhao, H. D., Zheng, H., De Long, L. E., & Riseborough, P. S. (2018). Electrical control of structural and physical properties via strong spin-orbit interactions in Sr 2 IrO 4. Physical Review Letters, 120(1), 017201.
• Cao, G., & Schlottmann, P. (2018). The challenge of spin–orbit-tuned ground states in iridates: a key issues review. Reports on Progress in Physics, 81(4), 042502.
• Zhao, H., Hu, B., Ye, F., Hoffmann, C., Kimchi, I., & Cao, G. (2019). Nonequilibrium orbital transitions via applied electrical current in calcium ruthenates. Physical Review B, 100(24), 241104.
• Cao, G., Zheng, H., Zhao, H., Ni, Y., Pocs, C. A., Zhang, Y., ... & Kimchi, I. (2020). Quantum liquid from strange frustration in the trimer magnet Ba 4 Ir 3 O 10. npj Quantum Materials, 5(1), 1–8.
• Ni, Y., Zhao, H., Zhang, Y., Hu, B., Kimchi, I., & Cao, G. (2021). Colossal magnetoresistance via avoiding fully polarized magnetization in the ferrimagnetic insulator Mn 3 Si 2 Te 6. Physical Review B, 103(16), L161105.
• Zhang,Y., Ni,Y., Zhao, H., Hakani, S., Ye, F., DeLong,L., Kimchi, I., and Cao, G.(2022), Control of chiral orbital currents in a colossal magnetoresistance material, Nature 611, 467–472, DOI: 10.1038/s41586-022-05262-3

References

1. "Gang Cao". Physics. July 13, 2016.
2. "Gang Cao (G. Cao)". scholar.google.com.
3. Cao, Gang; DeLong, Lance. "Physics of Spin-Orbit-Coupled Oxides". Oxford University Press.
4. "APS Fellow Archive". www.aps.org.
5. "Faculty Awards | Graduate School". gradschool.uky.edu.
6. Cao, G.; Terzic, J.; Zhao, H. D.; Zheng, H.; De Long, L. E.; Riseborough, Peter S. (January 4, 2018). "Electrical Control of Structural and Physical Properties via Strong Spin-Orbit Interactions in Sr2IrO4". Physical Review Letters. 120 (1): 017201. arXiv:1711.10021. doi:10.1103/PhysRevLett.120.017201. PMID 29350946. S2CID 206306107 – via APS.
7. Zhao, Hengdi; Hu, Bing; Ye, Feng; Hoffmann, Christina; Kimchi, Itamar; Cao, Gang (2019). "Nonequilibrium orbital transitions via applied electrical current in calcium ruthenates". Physical Review B. 100 (24). arXiv:1908.08571. doi:10.1103/PhysRevB.100.241104. S2CID 201645362.
8. Cao, G.; McCall, S.; Crow, J. E.; Guertin, R. P. (1997). "Observation of a Metallic Antiferromagnetic Phase and Metal to Nonmetal Transition in Ca3 Ru2O7". Physical Review Letters. 78 (9): 1751–1754. doi:10.1103/PhysRevLett.78.1751.
9. Cao, G.; McCall, S.; Shepard, M.; Crow, J. E.; Guertin, R. P. (1997). "Thermal, magnetic, and transport properties of single-crystal Sr1−xCaxRuO3 (0<~x<~1.0)". Physical Review B. 56: 321–329. doi:10.1103/PhysRevB.56.321.
10. Cao, G.; McCall, S.; Shepard, M.; Crow, J. E.; Guertin, R. P. (1997). "Magnetic and transport properties of single-crystal Ca2RuO4: Relationship to superconducting Sr2 RuO4". Physical Review B. 56 (6): R2916–R2919. doi:10.1103/PhysRevB.56.R2916.
11. Cao, G.; Durairaj, V.; Chikara, S.; Parkin, S.; Schlottmann, P. (2007). "Partial antiferromagnetism in spin-chainSr5Rh4O12,Ca5Ir3O12, andCa4IrO6single crystals". Physical Review B. 75 (13). arXiv:cond-mat/0612642. doi:10.1103/PhysRevB.75.134402. S2CID 51838039.
12. Cao, G.; Bolivar, J.; McCall, S.; Crow, J. E.; Guertin, R. P. (1998). "Weak ferromagnetism, metal-to-nonmetal transition, and negative differential resistivity in single-crystal Sr2IrO4". Physical Review B. 57 (18): R11039–R11042. doi:10.1103/PhysRevB.57.R11039.
13. Cao, G.; Xin, Y.; Alexander, C. S.; Crow, J. E.; Schlottmann, P.; Crawford, M. K.; Harlow, R. L.; Marshall, W. (2002). "Anomalous magnetic and transport behavior in the magnetic insulator Sr3Ir2O7". Physical Review B. 66 (21). doi:10.1103/PhysRevB.66.214412.
14. "Charge density wave formation accompanying ferromagnetic ordering in quasi-one-dimensional BaIrO3".
15. Cao, Gang; Schlottmann, Pedro (2018). "The challenge of spin–orbit-tuned ground states in iridates: a key issues review". Reports on Progress in Physics. 81 (4): 042502. arXiv:1704.06007. doi:10.1088/1361-6633/aaa979. PMID 29353815. S2CID 4036134.