Sort AlphaNumeric Data in Sql

The simple logic i used here is, extracted the number part from varchar and replaced it with 20 - length of that number (considering the no. of digits will not be more than 20 digits in varchar. Else increse the value 20).
First of all, create a Scaler valued Function as following:

ALTER FUNCTION [dbo].[AlphaNum]
(
	@input varchar(max)
)
RETURNS varchar(max)
AS
BEGIN
	declare @num varchar(50)
	declare @space varchar(50)
	declare @index int = 1
	
	set @num = LEFT(SUBSTRING(@input, PATINDEX('%[0-9.-]%', @input), 8000), PATINDEX('%[^0-9.-]%', SUBSTRING(@input, PATINDEX('%[0-9.-]%', @input), 8000) + 'X')-1)
	set @space = replicate(' ', 20 - len(@num))
	
	return replace(@input, @num, @space + @num)
END

How to Use:

select * from Department order by dbo.AlphaNum(DeptKey)

The result will be:

DepartmentId Department             DeptKey
------------ ---------------------  ------------------------
5            Main Admin             Admin1
3            Administrator          Admin2
1            Admin Permanent        Admin23
2            Admin on Contract      Admin45
4            Top Management         Admin100
7            Sales Team             Sales78
6            Trainer                Sales456

(7 row(s) affected)

Here, the result is alphanumerically sorted by DeptKey.