Theoretical and experimental investigation of the excellent p–n control in yttrium aluminoborides

Figures & data

Figure 1 Crystal structure of Y _x Al _y B₁₄.

Figure 2 Possible configurations of Y, Al, and B in a single orthorhombic unit cell of YAlB₁₄ with four formula units for (a)–(d) Y_0.50Al_0.25, (e)–(n) Y_0.50Al_0.50B₁₄, and (o)–(r) Y_0.50Al_0.75B₁₄.

Figure 3 Experimentally obtained Seebeck coefficient values of . New data for y = 0.39 is plotted together with data from [22]. Lines are a visual guide.

Table 1 Experimentally obtained structural parameters of Y _x Al _y B₁₄.

x	y	a axis (Å)	b axis (Å)	c axis (Å)
0.547(2)	0.394(4)	5.8458(8)	10.3401(14)	8.1766(11)
0.575(2)	0.411(3)	5.8118(6)	10.3518(10)	8.1889(8)
0.544(2)	0.532(4)	5.7816(7)	10.3409(12)	8.1444(9)
0.554(2)	0.601(4)	5.7947(7)	10.3757(12)	8.1609(10)
0.511(1)	0.620(3)	5.8182(3)	10.4105(5)	8.1901(5)
0.521(1)	0.634(2)	5.8162(3)	10.4082(7)	8.1886(5)

Table 2 Optimized structural parameters, and relative total energy per formula unit (fu). Here, the relative total energy is defined as the total energy difference from the energetically most stable configuration for x = 0.50 and each y. Indexing of the configuration is defined in figure 2.

	y	a axis (Å)	b axis (Å)	c axis (Å)	Relative total energy (eV/fu)
(a)	0.25	5.73	10.32	8.17	0.031
(b)	0.25	5.66	10.32	8.17	0.000
(c)	0.25	5.70	10.31	8.16	0.470
(d)	0.25	5.60	10.34	8.25	0.376
(e)	0.50	5.75	10.32	8.14	0.023
(f)	0.50	5.79	10.35	8.17	0.275
(g)	0.50	5.76	10.32	8.14	0.002
(h)	0.50	5.76	10.32	8.13	0.000
(i)	0.50	5.76	10.32	8.14	0.270
(j)	0.50	5.76	10.31	8.13	0.005
(k)	0.50	5.77	10.31	8.16	0.403
(l)	0.50	5.78	10.28	8.15	1.058
(m)	0.50	5.77	10.31	8.16	0.389
(n)	0.50	5.72	10.34	8.21	0.478
(o)	0.75	5.80	10.36	8.15	0.008
(p)	0.75	5.80	10.36	8.15	0.000
(q)	0.75	5.82	10.33	8.16	0.732
(r)	0.75	5.81	10.35	8.17	0.208

Figure 4 (a)–(c) Total density of states (DOS) and site-projected partial density of states (PDOS) at B2 and B5 for Y_0.50Al_0.25B₁₄ with the atomic configuration of figure 2(b). (d)–(k) Total DOS and PDOS of Y, Al, B1, B2, B3, B4, and B5 for Y_0.50Al_0.50B₁₄ with the atomic configuration of figure 2(h). (l)–(n) Total DOS and PDOS of B2 and B5 for Y_0.50Al_0.75B₁₄ with the atomic configuration of figure 2(p). The Fermi level corresponds to an energy of 0 eV.

Table 3 Al–B2 bond lengths and the corresponding number of bonds, n, for Y_0.50Al _y B₁₄. Indexing of the configuration is defined in figure 2.

	y	Length of Al–B2 bond ()	n
(b)	0.25	2.03	2
		2.05	2
(h)	0.50	2.06	8
(p)	0.75	2.03	2
		2.04	2
		2.05	2
		2.07	2
		2.11	4

Figure 5 (a)–(c) Isosurface of 0.78 electron for the electronic charge density of Y_0.50Al_0.25B₁₄, Y_0.50Al_0.50B₁₄, and Y_0.50Al_0.75B₁₄. Solid lines indicate the nearest neighbor inter-cluster bonds.

MaruyamaSMiyazakiYHayashiKKajitaniTMoriT 2012 Appl. Phys. Lett. 101 152101 10.1063/1.4748792

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