Antiferromagnetic bipolar semiconductor LaMnPO with ZrCuSiAs-type structure

作者：Yanagi Hiroshi^*; Watanabe Takumi; Kodama Katsuaki; Iikubo Satoshi; Shamoto Shin ichi; Kamiya Toshio; Hirano Masahiro; Hosono Hideo

来源：Journal of Applied Physics, 2009, 105(9): 093916.

DOI：10.1063/1.3124582

Electronic and magnetic properties of a layered compound LaMnPO are examined in relation to a newly discovered iso-structural superconductor LaFeAs(P)O. Neutron diffraction measurements, together with temperature dependent magnetic susceptibility, clarify that LaMnPO is an antiferromagnet at least up to 375 K. The spin moment of a Mn ion is determined to be 2.26 mu(B) at room temperature, and the spin configuration is antiparallel in the Mn-P plane and parallel between the Mn-P planes, which is rather different from that of LaFeAsO. Optical absorption spectra, photoemission spectra, and temperature dependent electrical conductivity indicate that LaMnPO is a semiconductor. Furthermore, nominally undoped LaMnPO exhibits n-type conduction while the conduction type is changed by doping of Cu or Ca to the La sites, indicating that LaMnPO is a bipolar conductor. Density functional calculation using the GGA+U approximation supports the above conclusions; the electronic band structure has an open band gap and the antiferromagnetic spin configuration is more stable than the ferromagnetic one.

• 出版日期2009-5-1